tivity on the carmel faul

Dating Paleo-seismic Ac<strong>tivity</strong> on the Carmel Fault
Using Damaged Cave Deposits from Denya Cave,
Mt. Carmel.
Yael Braun
This work was submitted as M.Sc. Thesis to the Institute of earth Sciences,
The Hebrew University of Jerusalem.
The study was carried out under the supervision of:
Prof. Amotz Agnon, Institute of Earth Sciences, Hebrew University of Jerusalem
Dr. Miryam Bar-Mathews, Geological Survey of Israel
Report GSI /23/2010 Jerusalem, October 2010

Acknowledgements
I would like to thank first and foremost my advisors for their unending patience
and understanding. I have learned a lot from them and benefitted tremendously from
their knowledge and experience.
I would like to thank Dr. Avner Ayalon for guidance and invaluable advice
through a lot of the work process. His knowledge and experience helped me
personally as well as professionally. I would also like to thank Elisa Kagan for
sharing her knowledge with me and helping me out whenever she could with good
advice and comforting words.
Special thanks go to the diligent workers of the Geological Survey of Israel who
simply do their work superbly and generously give of their time and experience: To
Shlomo Ashkenazi, Yaakove Mizrachi and Chaim Chemo for their help with the
technically challenging work in the cave; To Natalya Tapliakov for her help with
laboratory work and generous advice; To Dr. Irena Segal and Dr. Olga Yofe for
guidance and help with mass spectrometric analyses; To Bat-Sheva Cohen, Nili
Almog and Channa Nezer-Cohen for help with graphics and publications; and to all
the students who helped me learn the rudiments of lab work as well as helped me with
field work: Neta Shalev, Gilad Garber, Yuval Burstein, Nitzan Sheny, Yael Neumieir
and Eyal Merder. And to Mor Kanari for his help in field work as well as technical
matters, which always came with a smile and good humor.
I would also like to thank Dr. Moti Stein, Anton Vaks, Uri Ryb and Tami
Zilberman for very useful discussions which were valuable for the thinking process.
Thanks also go to Gal Hartman for his valuable contribution to the processing of
results in this study, both theoretically and practically.
Special thanks go to my father, Dr. Eliot Braun, who knows very little about
geology but a very great deal about writing, for his endless patience and extremely
valuable help in writing this thesis and all its subsequent publications.
Last but not least I would like to thank my good friends Leehi Magaritz and
Michal Laskow, who gave of their time to help sort out the occasional mess in my
head or help me out with computer programs and technical difficulties.
This research would not have been possible without the financial support of the
Israel Science Foundation (Grant #1006/2004).
2

Abstract
Mt Carmel is defined to its east by the NW-NNW Carmel fault, a branch of the Dead
Sea Transform System. Denya Cave, located on a spur of this mountain in Haifa,
Israel, is a karstic formation, in which broken speleothems, collapsed structures and
cracks were observed, and appeared to be evidence of seismically induced damage.
This study set out to determine whether broken and deformed cave deposits in Denya
Cave are speoleothem seismites from which information regarding the paleoearthquake
record of the region during the Quaternary might be extracted.
Following a process of mapping and investigating the cave and excluding non-seismic
causes for visible damage, possible samples were examined and extracted from those
deposits deemed most likely to have recorded ancient earthquakes. Unconformities in
stalagmites, stalactites and flowstone formations were identified as ‘seismic contacts’.
Laminae in such broken or deformed speleothems were then sampled for dating as
close as possible to their seismic contacts. The ages of these laminae, either preseismic
or post-seismic, define age constraints of damaging events.
A classification method for different types of seismites was added to speleo-seismite
analysis in order to determine reliability of results. This was determined according to
the type of speleothem, the clarity of the seismic contact as a viable indicator for a
seismic event, and the ability to adequately sample material.
Samples were dated utilizing the U-Th (uranium decay) method, a process that is not,
however, straightforward as the appearance of detrital matter within samples can alter
age determinations. Such adulterations necessitate corrections in order to yield true
ages. The ages obtained for Denya Cave seismite samples were corrected for detrital
Th using an isochron method based on isochrons. Seismite samples, which were
considered to be of the same age when certain criteria were met, were plotted along
isochron lines and a single age was determined for them. Criteria for plotting seismite
samples along isochron lines are based on stratigraphic considerations in the sample
laminae and the amount of detrital matter within the dated sample.
3

A total of 68 speleothem samples was taken and inspected from Denya Cave, 37 of
which were identified as seismites; of them, 32 were processed. Ten seismites are
severed stalagmites broken along sub-horizontal plains. Nine seismites of the 32 are
severed stalactites of different shapes and sizes. The remaining seismites are
flowstone samples in which breaks and depositional unconformities were found; some
revealed soda straw speleothems embedded in them.
The isochron calculated ages obtained for groups of speleo-seismite samples indicate
that each group records a seismic event. Nine age clusters were determined for speleoseismites
from Denya Cave, indicating the ages of seismic events which affected the
cave over the last 200ky: 4.8±0.80ka; 10.42±0.69ka; 20.8±3.0ka; 29.1±3.3;
38.0±2.7ka; 57.9±5.2ka; 137±29ka; 147.6±5.4ka and 160±45ka.
A comparison with data available to date from other paleoseismological studies in the
region shows that all ages obtained for Denya Cave age clusters can potentially be
compared to other ages obtained from other studies in Israel. The comparison
indicates that the breaks identified in Denya Cave speleothems, are not random and
lends supportive evidence to the assumption that they represent seismic events. Some
of the ages obtained from this study might coincide with ages of seismic events dated
along the Dead Sea Transform, as well as those along the Carmel Fault. Therefore,
future studies are required in order to determine the origin of paleo-earthquakes
reported in this study.
4

Table of content
1. Introduction................................................................................................................8
1.1 General introduction ............................................................................................8
1.2 Basic assumptions for paleoseismic research using speleothems........................9
1.2.1 Previous studies ..........................................................................................10
1.2.2 Basic assumptions for paleoseismic research in Denya Cave ....................12
1.3 Dating of Speleothems.......................................................................................14
1.4 Geological setting of Carmel region..................................................................16
1.4.2 Geological features of Denya neighborhood on Mount Carmel.................25
2. Research Objectives.................................................................................................32
3. Methodology............................................................................................................32
3.1 Mapping .............................................................................................................32
3.2 Speleothem sampling.........................................................................................32
3.3 Dating of seismite samples ................................................................................35
3.3.1 Multiple Collector Inductively Coupled Plasma Mass Spectrometer.........35
3.3.2 Single sample dating...................................................................................36
3.3.3 Cluster dating..............................................................................................45
4.1 Single sample age analysis.................................................................................47
4.2 Age cluster analysis ...........................................................................................54
4.2.1 Seismic events in Denya Cave....................................................................64
4.2.2 Isochron age cluster dating .........................................................................65
5. Discussion................................................................................................................71
5.1 Seismic events recorded in Denya Cave speleothems .......................................71
5.2 Comparison of results with other paleoseismic studies .....................................72
5.2.1 Considerations for comparisons between paleoseismic studies..................77
5.1.2 Suggestions for further research .................................................................78
6. Conclusions..............................................................................................................79
7. References................................................................................................................79
5

List of figures
Figure 1: Geological map of Mt. Carmel. 19
Figure 2: DEM map (Hall, 1996) illustrating the CF and GF (Gilboa Fault) and their relation to
the DST. 20
Figure 3: Morphotectonic mapping of displaced stream channels in a segment of the CF between
Jalame and Yoqneam. 23
Figure 4: Location of earthquake epicenters (M>2) in the vicinity of the CF system for the years
1980-2000. 24
Figure 5: Earthquakes for the years 1980-2007 along the CF and adjacent areas and the DST,
and their respective magnitude distribution. 25
Figure 6: Topographic map (1:50,000) of NW Mt. Carmel. 26
Figure 7: Geological map of the northeastern side of Mt. Carmel (Karcz, 1958). 27
Figure 8: Part of a preliminary fault map of central and southern Mt. Carmel (Segev and Sass,
2006). 27
Figure 9: Pictures from a quarry in Denya neighborhood, Haifa. 29
Figure 10: Plan of upper chamber in Denya Cave, Haifa. 30
Figure 11: Seismic features in Denya Cave. 31
Figure 12: Pictures from the lower chamber of Denya Cave. 31
Figure 13: Denya Cave seismite clasification. 34
Figure 14: Sample DN-7 35
Figure 15: Photographic ilustration of the location of drilling for isochron samples: DN-4 Iso,
DN-4 Iso2 and DN-17 Iso. 40
Figure 16: Photographic ilustration of the location of drilling for isochron samples: DN-16 Iso,
DN-35 Iso, DN-53 Iso and DN-62 Iso. 41
Figure 17: Dated seismite uncorrected ages. 51
Figure 18: Sample stacking plot. 52
Figure 19: U-series evolution diagram for Denya Cave seismite samples. 55
Figure 20: 5ka sample age cluster. 56
Figure 21: Age cluster ~5ka samples. 56
Figure 22: 10.4ka sample age cluster. 57
Figure 23: Age cluster ~10.5ka samples. 57
Figure 24: 21ka sample age cluster. 58
Figure 25: Age cluster ~21ka samples. 58
Figure 26: 29ka sample age cluster. 59
Figure 27: Age cluster ~29ka samples. 59
Figure 28: 38ka sample age cluster. 60
Figure 29: Age cluster ~38ka samples. 60
Figure 30: 58ka sample age cluster. 61
Figure 31: Age cluster ~58ka samples. 61
Figure 32: 137ka sample age cluster. 62
Figure 33: Age cluster ~137ka samples. 63
Figure 34: 148ka sample age cluster. 63
Figure 35: Age cluster ~147ka samples. 64
Figure 36: 160ka sample age cluster. 64
Figure 37: Age cluster ~160ka samples. 64
Figure 38: U-series evolution diagram for Denya Cave seismite samples showing the projected
data. 68
Figure 39: U-series evolution diagrams for Denya Cave seismite samples showing uncorrected
ages. 69
Figure 40: Comparison between Denya Cave cluster results and other paleoseismic studies in the
region. 76
6

List of Tables
Table 1: Isochron sample's results of low detrital content samples. 40
Table 2: Isochron sample's results of low detrital content samples. 41
Table 3: Isochron sample's results of low detrital content samples. 42
Table 4: Results of an experiment in order to determine the nature of the detrital component
found in samples from Denya Cave. 44
Table 5: Denya Cave seismite I.D.'s 49
Table 6: Dated seismite samples' isotopic ratios and uncorrected ages. 53
Table 7: Comparison between the ages obtained by different dating techniques for Denya Cave
seismite samples. 70
Table 8: Comparison between Denya Cave cluster results and other paleoseismic studies in the
region. 75
7

1. Introduction
1.1 General introduction
Mt. Carmel, a continental uplift of more than 500m above sea level in the north of Israel,
is a manifestation of tectonic movements. The uplift is defined by a NW to NNW fault, which
is a branch of the Dead Sea transform (DST) system that continues into the Mediterranean
continental shelf (Hofstetter et al., 1989). The Carmel Fault (CF) is observed as a zone of
deformation, rather than a single fault trace (Rotstein et al., 1993). The fault has been active
since the Miocene and evidence for ac<strong>tivity</strong> during the Pleistocene has been documented; yet
very little is known about the extent of seismic ac<strong>tivity</strong> on the CF during the Quaternary
(Gluck, 2002). On August 24 1984, an earthquake of a magnitude (M L ) of 5.3 caused slight
damage in Haifa and adjacent towns (Hofstetter et al., 1996). That earthquake aroused the
interest of many since not much was known about the extent of seismic ac<strong>tivity</strong> in the environs
of Mt. Carmel. It also emphasized the importance of understanding the tectonic regime of that
part of Israel as noted by Hofstetter et al. (1989). In a later article Hofstetter et al., 1996
presented data on a series of about 550 earthquakes (1.0≤M L ≤5.3) along the Carmel-Tirtza fault
during a ten year interval (1984-1994). Their analysis yielded information that further indicates
the significance for understanding this specific fault system and the earthquakes it might
produce.
The record of paleo-earthquakes in the Israel region is based on many independent
sources ranging from historical and archeological evidence to geomorphological and
geological findings (e.g. Amiran et al., 1994; Marco et al., 1996; Ellenblum et al., 1998; Enzel
et al., 2000; Migowski et al., 2004; Begin et al., 2005; Agnon et al. 2006). The possibility of
extending that earthquake catalog, even if limited only to major earthquakes, can provide
fundamental elements for seismotectonic knowledge, seismogenic descriptions and
consequently, the evaluation of seismic hazards of the area.
Scholars (e.g. Becker et al., 2005, 2006; Kagan et al., 2005) agree that a fundamental
aspect of a concise earthquake catalog is based on a multi-archival approach. Using different
types of paleo-earthquake proxies not only enables confirmation of each of the separate
findings, but allows for a better understanding of spatial influence of earthquakes on different
geological environments and their connections to tectonic settings of the region.
Broken or deformed cave deposits (speleo-seismites) can be used for paleoseismic
research since they can be dated with radiometric techniques (e.g. Forti, 1998; Davenport,
8

1998; Lacave et al., 2004; Kagan et al., 2005; Panno et al., 2006). The dating of seismites
contributes to an earthquake data base as an independent source of information and can also
indicate frequency of major earthquakes (Kagan et al., 2005). Furthermore, an analysis of the
physical features of seismites could allow better understanding of the tectonic mechanism
which produces them (e.g., Kostov, 2002). Anthropogenic, climatic, glacial movements and
other non seismic activities can cause deformation and breaking of speleothems, and therefore
it is required to eliminate them as factors in determining seismic ac<strong>tivity</strong> (Becker et al., 2006).
In a study conducted in caves in the Judean Mountains (Kagan et al., 2005), earthquake
sequences were corroborated by independent evidence, clearly showing that data derived from
broken speleothems enables precise dating and in-depth analyses of ancient earthquakes. The
Carmel region has some karstic features that can serve as a basis for a paleo-seismological
study of the fault system that defines it, enabling a further enlargement of the data base
currently available, and perhaps allowing for a better understanding of it. The U-Th dating
method, which has a 350 to 500kyr limit, can vastly increase the length of the seismic record in
the Quaternary.
1.2 Basic assumptions for paleoseismic research using
speleothems
Special environments in caves help to maintain seismic evidence in good condition,
protecting against erosion and degradation. Calcitic cave deposits grow in a laminar pattern
and therefore preserve a very detailed record of events, namely climatic (e.g. Frumkin et al.,
1999; Bar-Mathews et al, 2003), and some tectonic ones. Speleothems can be dated with
radiometric methods so it is possible to observe a sequence of this type of event (Kagan et al.,
2005).
Effects of earthquakes on caves and speleothems can come in different forms such as
collapsed speleothems and rockslides due to earth movements or changes in growth axes due to
tilting and closing or opening of cracks, depending upon their locations in relation to stress
fields (e.g., Forti, 1998; Muir-Wood and King, 1993; Morinaga et al., 1994; Gilli et al., 1999;
Lemeille et al., 1999). Aside from dating, which can indicate a sequence of paleoseismic
events (Kagan et al., 2005), analysis of these elements can help constrain locations and
epicenters of earthquakes as well as their magnitudes (Forti, 1998) or peak ground acceleration
(PGA) generated by them (e.g. Lacave et al., 2004; Szeidovitz et al., 2008). With these ideas in
mind, many studies have been conducted on damaged caves in different places around the
9

world in order to chronologically reconstruct principal paleoseismic events and to estimate the
maximum earthquake possible in a given seismogenic area.
1.2.1 Previous studies
A number of studies are of particular relevance to this discussion. Postpischl et al. (1991)
took samples of growth anomalies in stalagmites from the “Grotta Del Cervo” and the “Grotta
a Male” (caves in central Italy), and dated them using 14 C and U/Th radiometric methods.
Observing the anomalies, they found they are always related to earthquakes or other tectonic
events. They also found that collapsed stalagmites presented preferential azimuths,
demonstrating an involvement of the entire karst area and therefore, the tectonic character of
the event which generated a particular collapse. They associated these collapse formations with
four different seismic periods of ac<strong>tivity</strong>, the youngest of which is most probably related to the
December 1456 earthquake that occurred in central Italy.
Morinaga et al. (1994) inferred paleo-seismicity from paleo-magnetic dating of
speleothems in western Japan. Those researchers claimed that in areas of active seismicity,
earthquakes can contribute to a condition in which blocks are “ready to collapse”. Using data
on weak, yet stable remnant magnetization of speleothems, they determined the Paleo-Secular
Variation (PSV) of a geomagnetic field, which they then compared to a standard curve in order
to establish the time of growth. In that study three stalagmites, which were perched on
collapsed limestone blocks, yielded three ages interpreted to indicate dates of past earthquakes.
In order to validate this research method, Lemeille et al. (1999) conducted research in
regions where earthquakes are studied and known from historic based catalogues. A regional
study was carried out in the vicinity of Basel (Switzerland), the area of the greatest damage
during the historically dated earthquake of 1356 CE. They explored and analyzed growth
anomalies and displacements of speleothems in two karstic caves. Battlerloch Cave yielded a
fallen block from which dating samples of re-growth phases were taken in order to confirm
their seismic origins. Dieboldslochli Cave revealed a large number of broken stalagmites; the
offset of re-growth on the fault plane is assumed to be related to a number of events, all of
which could have been caused by earthquakes. Moreover, some preliminary data on ages of
these anomalies corresponded to the 1356 CE earthquake.
Similar studies were carried out by Gilli et al. (1999), who investigated eight caves near
St. Paul de Fenouille in the eastern Pyrenees (France), following an earthquake of magnitude
5.2 in February 1996. That kind of study has the advantage of knowing the age of the damage
and the accurate magnitude of an event. Collapsed soda straw stalactites and small rocks were
observed and attributed to the earthquake. Other more ancient damage was also noted. A
10

statistical study indicated that the main direction of the collapsed soda straws was in
accordance with the E-W movement of the fault associated with the earthquake. Numerical
simulations confirmed that soda straw stalactites are relatively strong objects that may break
during earthquakes under certain conditions.
Kostov (2002) identified deformations in speleothems, with possible co-seismic origin in
two caves in the Balkan Range and Rhodope Mts. (Bulgaria). In Lepenitsa Cave, orientation of
68 broken stalagmites was measured and showed an expressed preference to be aligned with
the direction of the epicenters of the strongest known earthquakes in the area. This direction
did not coincide with the direction of flow in the caves sediments, which precludes an
assumption that they might have been displaced by sediment creep (Gilli et al., 1999).
Moreover, the stalagmites had fallen on a flat, stable, horizontal floor in a manner that excludes
the possibility of secondary deposition. Shepran Cave is situated about 55km to the southwest
of the epicenter of a 1928 Ms=7 earthquake, during which there were eyewitnesses to the
collapse of several speleothems. By 2001, several speleothems in this cave had a calcitic
growth on them. One of the maxima in the distribution of directions of the fallen stalagmites
corresponds to the epicenter of the earthquake.
Kagan et al. (2005) introduced a rigorously dated record of earthquakes from an
extensive number of well preserved pre- and post-seismic precipitates from caves located off
the Dead Sea Transform (DST) in the Judean Hills, near Jerusalem. Covering an 185ky
interval, they dated 38 seismite samples which they attributed to 13-18 earthquakes, with a
mean recurrence interval of ~10-14ky. They also showed that these events complement
independent, near-fault paleoseismic records. Seismites in the studied caves (at Har-Tuv and
Soreq) include collapsed stalagmites, stalactites, speleothem pillars and cave ceilings overlain
by re-growth, as well as stalagmites with severed tops and collapsed objects imbedded in
flowstone. In addition they noted an abundance of predominantly horizontal fissures in
speleothems and in the cave walls. Mapping of the Soreq Cave revealed preferential
orientations of collapsed long-axis speleothems which were oriented N-S and E-W. Dating
revealed the simultaneity of the collapses.
More than two thirds of the ages of seismites concur with ages derived from other
seismites presented in their study, which indicate that the record produced approximates the
actual distribution of destructive earthquakes. Moreover, six paleoseismic events that occurred
during the past 75ky are identified and dated by 20 damaged speleothems.
In work which started in 2001, Panno et al. (2006) studied two caves in southwestern
Illinois located within 250km of the New Madrid Seismic Zone (NMSZ) and within 150km of
11

epicenters of the 1811 and 1812 earthquakes. In those caves they found geological features that
appeared to be related to earthquake ac<strong>tivity</strong> including stalagmites with deviated growth axes,
fallen stalactites in an isolated area in one of the caves and hundreds of newly grown and still
active speleothems growing on older speleothems and breakdowns. Using the U-Th mass
spectrometry method, they dated three new speleothems from both caves and concluded that a
single event triggered their growth. They suggest two scenarios which could have reopened
former flow paths to the caves: (1) the 1811-1812 NMSZ earthquake series or (2) the
beginning of agricultural ac<strong>tivity</strong> on the surface in the early 1840s.
Following the Nia (Indonesia) earthquake of 2005, Aydan (2008), in his study of the
Gunung Sitoli Cave noted quite a few earthquake related features, which he found to be newly
formed and which he believes to be associated with that recent event (ruptured columns and
stalactites, fallen stalactites and rock blocks and separated slabs with a new growth phase along
them). Some of these features were newly formed on top of old ruptures and breaks, which he
associates with other seismic events in that highly active region.
All of the studies cited above are part of a growing body of evidence. They support the
growing belief that speleothems could be very good archives of seismic ac<strong>tivity</strong> in their
respective regions. Two main considerations should be taken when approaching this method of
dating paleo-earthquakes, namely the various other mechanisms that could cause damage in
speleothems, and the not yet fully understood mechanisms which allow for the rupture of most
speleothems.
1.2.2 Basic assumptions for paleoseismic research in Denya Cave
Following the above mentioned work of Kagan et al. (2005) in the Judean Hills, which
provided ages consistent with independent evidence for strong earthquakes, similar research
techniques were applied to Denya Cave in order to examine paleoseismic ac<strong>tivity</strong> on the CF.
While there is some similarity between the two areas, there is also one major difference, which
is the abundance of paleoseismic evidence for the DST. As noted above it contributes to the
credibility of results, whereas paleoseismic evidence on the CF for the Quaternary is virtually
non existent. The assumption is made for Denya Cave that success of a previous study allows
for an attempt at reconstructing earthquake data in the Carmel region using the same methods.
Furthermore, as cited above, studies of this kind from around the world validate this method of
dating paleo-earthquakes (e.g. Postpischl et al., 1991; Lemeille et al., 1999; Panno et al., 2006)
and evidence of broken speleothems due to recent earthquakes is likewise well documented
(e.g. Gilli et al., 1999; Kostov, 2002; Aydan, 2008).
12

The first step in establishing viability is the exclusion of all other non-seismic causes for
damage in Denya Cave. Becker et al. (2006) compiled all non-seismic alternative causes for
damage, which needed to be refuted for Denya Cave:
1. Anthropogenic sources—recent damage by construction of the Denya neighborhood
can be distinguished from less recent seismic events by morphological assessment
(Crispim, 1999) and dating. Initial results indicate that ages of damage are within the
range of thousands of years or more. Human and animal ac<strong>tivity</strong> in the cave is ruled
out as sources of damage since the cave was closed to the surface until its artificial
opening in the twentieth century CE.
2. Underground glaciers and ice creep or frost action—in this part of the Levant cave
temperatures were significantly above freezing during the period investigated
(Frumkin et al., 1999; Bar-Matthews et al., 2000; Ayalon et al., 2002).
3. Erosion and soil creep—water circulation in the cave seems to be of a very low
energy and no areas of the cave seem to have sediment fills that show any signs of
creep.
4. Flood and debris flow—as well as a lack of evidence of sediment fills, the overall
structure of the cave does not seem to show any signs of flooding. Furthermore, there
doesn’t seem to be any convenient water source that could cause a major flood in the
area or any aperture whereby a large amount of water could enter and/or exit the cave.
5. Incations (cave instability that may result in rock fall or the collapse of whole cave
sections)—these occurrences may well be the result of earthquakes, but might also be
due to gravitational effects caused by the instability of crevasses or the overall
construction of karstic cavities. There is some evidence of subsidence in Denya Cave.
The lower chamber collapsed onto itself, but the cause or date of the event cannot be
deduced from what we know. The assessment that the collapse was caused by seismic
ac<strong>tivity</strong> is based on three assumptions: (1) in this chamber bedrock layers are still
horizontal, confirming that no tilting movements caused the incation. (2) evidence for
corroborative data can be found in other, nearby caves (see ch. 1.4.2 and Fig. 9); (3)
the Carmel region is seismically active, and thus, affirms the likelihood of earthquake
damage there. Observations of this kind will be elaborated below (see ch. 1.4.1-
Seismicity of Mt. Carmel).
6. Slope movements—these too can be triggered by earthquakes, but may also be
considered as expressions of common slope degradation processes in rapidly uplifting
terrains with deeply incised river valleys. Mt. Carmel is considered to be an uplifting
13

terrain (see ch. 1.4- Geological setting of Carmel region), yet no direct evidence of
slope movement in the area of Denya Cave was found to date. Landslides were
documented mostly on the northeastern slopes of the Carmel.
The elimination of these points allows for the working hypothesis that earthquakes
caused the observed damage to speleothems in Denya Cave.
1.3 Dating of Speleothems
In the 238 U radioactive decay-series a state of secular equilibrium between parent and
daughter nuclides is established in any naturally occurring material that has remained
undisturbed for several million years because the half-life of the parent isotope is much greater
than that of the intermediate daughters in the decay chain. The decay-series in secondary
deposits formed from the dissolution and subsequent precipitation of such material, however,
will be in a state of disequilibrium at time of formation, with either an excess or deficiency of
intermediate nuclides because of fractionation processes. The extent to which it has returned to
secular equilibrium in a closed system from an initial state of disequilibrium can be expressed
by a straightforward function of time using the decay constants if the following criteria are
satisfied: (1) intermediate and daughter decay products at time of formation were absent, or if
present, can be corrected for; (2) no gain or loss of the parent nuclide or daughter products
occurred since the time of formation (Richards and Dorale, 2003).
U-series dating of speleothems is based on the extreme fractionation of the parent 238 U
isotope from its long-lived daughter 230 Th in the hydrosphere. The average abundances of U
and Th in the earth’s continental crust are 1.7 and 8.5 µg/g respectively (Wedepohl, 1995).
Their relative abundances in the hydrosphere are different principally because of their differing
solubility in surface and near surface environments (Richards and Dorale, 2003).
U is readily mobilized in the meteoric environment, principally as the highly soluble
Uranyl ion (UO 2+ 2 ). The long-lived daughter product Th exists in a +4 oxidation state and is
readily hydrolyzed and either precipitated or absorbed on detrital particulates. It can therefore
be readily transported with the result that waters feeding secondary calcite deposits will
generally have negligible Th concentrations. In a closed system, the extent to which 230 Th/ 238 U
ac<strong>tivity</strong> (a) ratios have returned to unity is a function of time (t).
Calcite speleothems can be dated accurately by U-series disequilibrium techniques under
specific conditions: (1) when the system remained closed to the addition or removal of U or Th
nuclides to the lattice; (2) when the deposit is younger than ~500,000y; (3) when there is a
sequential stratigraphic layering along the growth axis; (4) when there is no initial Th in the
14

crystal lattice; (5) when detrital Th is known and corrected for (Kaufman et al., 1998); (6)
when analytical and counting errors as well as decay constants are known.
As mentioned above, a U-series radionuclide system should be closed to postdepositional
migration or addition constituent nuclides. Material analysis should be done in
order to avoid working with the following materials: (1) Authigenic material that shows
evidence of weathering. (2) Any sign of recrystallization, such as conversion from aragonite to
calcite, since it is indicative of potential nuclide migration (Bar-Matthews et al., 1997). Denya
Cave speleothems are dense, macrocrystalline calcites, showing no weathering and
recrystallization effects. In addition, the cave was closed to the surface until the construction of
Denya neighborhood. It is therefore assumed that Denya Cave is a closed system.
In this study dating with the 230 Th/U method was conducted on a Multiple Collector
Inductively Coupled Plasma Mass Spectrometer (MC-ICP-MS), which produces high
analytical precision and enables work on a small sample (~0.1g) that in turn gives ages at a
high resolution, due to the ability to sample individual laminae. Results may yield ages which
have an error margin of ca. 1% or less.
For reasons which are explained bellow (ch. 3.3- Dating of seismite samples) two sets of
ages are presented in this study;
1. Based on age equation [1] according to Broecker and Kaufman (1965):
[1] [ 230 Th/ 234 U] = [ 238 U/ 234 U]*(1-e -λ230t ) + {1-[ 238 U/ 234 U]}*{λ 230 /(λ 230 -λ 234 )}*[1-e (-λ230-λ234)t ]
The calculation of age is done using the Newton-Raphson iteration in which the final age and
the analytical error (±2σ) is given. This equation was used for dating single samples.
2. Based on age equation [2] according to Broecker (1963):
[2] [ 230 Th/ 238 U] = (1-e -λ230t ) + {[ 238 U/ 234 U] - 1}*{λ 230 /(λ 230 -λ 234 )}*[1-e -(λ230-λ234)t ]
The calculation of age is done using Isoplot3.7 by Ludwig (2008) with a first derivative
estimation for samples of similar ages plotted on isochron lines (sample age clusters). Here too
the analytical error (±2σ) is given.
In both equations the constants are:
λ 230 = 9.195 x 10 -6 y -1 – 230 Th constant
λ 234 = 2.835 x 10 -6 y -1 – 234 U constant
t –years.
All ratios presented here and in the following passages in brackets represent ac<strong>tivity</strong>
ratios. Those equations are based on the assumption that no initial 230 Th is present in the
sample and that all of the U is derived from the water, rather than from detrital material or
other sources. These assumptions hold well for speleothem samples containing negligible
amounts of detrital Th, but a correction must be made for it in all other samples. Initial 230 Th is
15

generally considered to be associated with a detrital component that becomes cemented, or
occluded within the speleothem. This component may be composed of clays, alumino-silicates
or Fe-oxyhydroxides with strongly absorbed Th 4+ . Th incorporated in speleothems may also
have been transported in colloidal phases, attached to organic molecules or as carbonate
complexes in solution (Richards and Dorale, 2003 and references therein).
The extent of initial Th contamination can be monitored by measurement of 232 Th, which
is the most abundant, extremely long lived isotope of Th with a half life of 1.401x10 10 y. Where
232 Th content is high, initial 230 Th concentration is also expected to be significant. To a first
approximation, correction can be made for the detrital component of 230 Th by using the 232 Th
concentration as an index of contamination and assuming an appropriate value of 230 Th/ 232 Th
for the sedimentary context. By assuming that 232 Th was incorporated at the time of
contamination, and that the excess 230 Th associated with this 232 Th decayed over time since
then, in situ ingrowth within the authigenic carbonate phase can be calculated. The
concentrations of 234 U and 238 U in the authigenic carbonate are assumed to equal their
concentrations in the lechate that includes the portion of detritus that has entered solution
(Richards and Dorale, 2003).
Two methods of age corrections for initial 230 Th have been attempted in this study; (1)
Finding a correction value for the Denya Cave depositional environment. This was initially
attempted by using the isochron method suggested by Kaufman et al. (1998) as was done for
Soreq Cave. Later on a direct approach to finding this correction value was applied. (2) Using
the isochron method based on Osmond type isochrons as suggested by Ludwig and Titterington
(1994), applied using Isoplot3.7 (Ludwig, 2008). Both methods and their consequent results
are further discussed below (ch’s. 3, 4- Methodology and Results).
1.4 Geological setting of Carmel region
Studies based on geophysical evidence suggest the continental margin west of the DST
is divided into two major provinces, the boundary between which is the CF system and its
postulated continuation offshore (Hofstetter et al. 1991; Ben-Avaham and Ginzburg, 1990;
Garfunkel and Almagor, 1985).
The northern CF is part of a fault system that begins at the Beth-Shean area of the DST
and extends into the continental shelf of the eastern Mediterranean (Fig. 2; Schattner et al.,
2006; Ben-Avraham and Hall, 1977). This system is a secondary branching of the DST
(Freund, 1965). Freund et al. (1970) found a connection between the DST and young faulting
trends in Eastern Galilee and in Lebanon, and concluded that this intense faulting trend is
16

caused by curved segments along the DST. Geophysical studies suggest that the crust,
including the continental shelf is divided into two, and that the CF system is the boundary
between them. The southern part includes central Israel and the northern part includes Galilee
and Lebanon (Garfunkel and Almagor, 1985; Ben-Avraham and Gintzburg, 1990; Hofstetter et
al., 1991).
The CF, which follows a general NW to SE direction (Fig. 1), is a set of many small fault
strands and has distinct tectonic and morphological expressions (Hofstetter et al., 1996). The
fault zone is quite complex with a terrestrial uplifting of about 500m above sea level. The CF
and its continuation as the Gilboa Fault (GF) together combine to create a seismically active
zone stretching for approximately 130km (Fig. 2; Hofstetter et al., 1996). Given that the
seismic ac<strong>tivity</strong> in the Galilee coastal plain is connected to the continuation of the fault in the
Mediterranean (Ron et al., 1984; Achmon, 1986; Ben-Gai, 1989), the fault zone stretches more
than 170km. Rotstein et al. (1993) carried out a series of high resolution seismic lines crossing
the CF zone, which permitted a detailed analysis of its shallow structure and nature. According
to their analysis the CF is a wide zone of intense deformation rather than a single fault trace. In
the Jezreel Valley the deformation is limited to an approximately 800m wide zone and appears
to be associated with pure strike-slip motion. East of Mt. Carmel the fault changes trend from
NW-SE to about N-S, and coincides with a zone of intense deformation at least 3km wide.
North of Mt. Carmel, where the fault resumes its NW-SE trend, it is nearly vertical at depth.
The development of movement along the CF system with time has been addressed by
different studies. Ben-Avraham and Gintzburg (1990) suggested that the CF originates in a
Paleozoic suture line between accreted terrains, which they linked to the closure of the Paleo-
Tethys. Achmon and Ben-Avraham (1997) suggested three major stages of tectonic
development: A Triassic-Jurassic rifting phase due to a N-S opening of the Neo-Tethys. A
compressive phase of the Late Miocene, which they suggest causes left lateral strike-slip
movement along the CF zone, where some of the older faults are reactivated. An uplifting
phase during the Pliocene-Pleistocene, in which most of the faults are reactivated as normal
faults, and the region of the Carmel, Umm-El-Fahm and the Gilboa are raised and tilted to the
southwest. The extent of the uplifting movement of Mt. Carmel during the Pliocene-
Pleistocene to the present has not yet been clearly resolved.
The Carmel region is an isolated mountain range in northwestern Israel (Fig. 1). Upper
Cretaceous marine rocks are exposed (Kashai, 1966; Karcz, 1958) along with volcanic
intercalations (Sass, 1980) and marine Paleogene rocks (Karcz, 1958). The stratigraphic
sequence shows limestones, dolomites, chalk and marls (Sass, 1957; Karcz, 1958; Kashai,
17

1966), which are exposed throughout the area. These are indicative of a depositional
environment of a continental shelf margin (Sass, 1980; Sass and Bein, 1982).
Mt. Carmel, an uplifted block tilted to the southwest, is defined on its northeastern side
by the CF (Fig. 1; Achmon, 1986; Kafri, 1969,1970; Karcz, 1959). In general it is an
asymmetrical anticline, about 50km long, with smaller anticlines and synclines that run parallel
to the main anticline (Kashai, 1966; Picard and Kashai, 1958). To the north of Isfiya-Shalala
Fault (Fig. 1), which has a generally E-W orientation, the fault pattern is different from that on
its south side. In the northern area there are a few individual fault strands that show a vertical
displacement of several meters. To the south, the fault system spreads in a fan-like formation
from a N-S direction in the west to an E-W direction in the east (Fig. 1; Kashai, 1966). The
displacement on this system ranges between 1300 to 2900m (Sass, 1980; Sass et al., 1977).
According to Ron et al. (1990 and 1984) the movement along those faults is due to rotations of
blocks of the southern and northern parts of Mt. Carmel. These scholars showed the southern
faults to have one set of N-S trending left lateral strike-slip, and three minor sets of E-W
trending right lateral strike-slip, NW trending normal and NW trending left lateral oblique
normal faults. They conclude that oblique displacement is superimposed on pre-existing
normal faults.
18

1
2
Yagur
Jalame
3
4
Yoqne’am
Meggido
Figure 1: Geological map of Mt. Carmel (Sneh et al., 1989). Denya Cave area is marked by a yellow
frame. Blue arrows mark the research areas of: 1. Salamon et al. (2001) and Zilberman et al. (2006); 2.
Feigin (1994) & Gluck (2002); 3. Gluck (2002); 4. Zilberman et al. (2006). DST and CF fault map
modified from Salamon et al., 2003.
19

Denya
Cave
Hall, 1996
Figure 2: DEM map (Hall, 1996) illustrating the CF and GF (Gilboa Fault) and their relation to
the DST.
20

1.4.1 Seismicity and paleo-seismicity of Mount Carmel
The recent ac<strong>tivity</strong> of the CF is evident in the steepness of its cliffs, displaced stream
channels (e.g. Fig. 3) and its frequent micro-earthquakes (Marco et al., 2006). Ashkar et al.
(2005) list some surface phenomenon indicating ac<strong>tivity</strong> along the CF and yet, they
conclude that although there are many, the pace and amount of movement on the fault are
still not clear.
According to data collected by the Geophysical Institute of Israel, between the years
1940 to 2007, 41 earthquakes (2.0

vertical offset. Dating of sand samples yielded an age of approximately 55ka (OSL
method). This age was interpreted to suggest a normal faulting at a rate of 0.2mm/y.
Zilberman et al. (2006) found evidence for two tectonically active periods in a trench
dug perpendicular to the Nesher fault (Fig. 1). Dating with the OSL method yielded the
following ages: (1) late, middle Pleistocene (ca. 176,000y) and (2) late Pleistocene
(between 75,000 and 27,000y). The evidence from the Nesher fault does not allow for a
determination of the age or magnitude of seismic events, but does provide evidence for
ac<strong>tivity</strong>. Since the trench was dug along a secondary fault, Zilberman et al. (2006) assumed
that their findings represent only part of the paleoseismic ac<strong>tivity</strong> along the main fault. No
evidence for Holocene ac<strong>tivity</strong> was found, but it is noted that during that period the
research area was subjected to human ac<strong>tivity</strong> which did not allow sediments to accumulate
and therefore preserve evidence of tectonic movements. In the same study Zilberman et al.
(2006) observed a shutter ridge across a stream valley between Yoqneam and Jalame that
was formed by a left lateral movement of the N-S segment of the CF. At the back of the
ridge evidence of a slow stage of sedimentation between the Late Pleistocene up until ca.
24,500y ago was found. Another, faster sedimentation stage is dated to 3,500-2,500y. Both
those ages were obtained using the OSL method as well. The authors considered the
movement of the fault as a possible cause for these sedimentation stages due to a temporary
blockage of the stream valley.
The site of Megiddo is situated close the the trace of the CF (Fig. 1) and has
reasonably well-dated archaeological strata. These attributes prompted an archeo-seismic
study of the site by Marco et al. (2006). They reported structural damage of potentially
seismic origin in several strata, two of which are particularly well dated. One is of the late
4 th millennium BCE, where monumental walls of an Early Bronze (EB) I temple are
fractured in several places along their strike as well as perpendicular to the strike. The
overlying walls of the EB III temple were no fractured, which constrains the age of the
earthquake. The other seismic event which caused structural damage is dated to the 9 th
century BCE. This observation is based on several findings throughout the site (e.g. tilted
pillars, tilted buildings) all dated to Iron II. They further concluded that biblical indications
for a major earthquake in ca. 760 BCE seem to coincide with the damage found for 8 th
century BCE buildings. All ages are based on accumulated evidence derived from chronocultural
identification of archaeological contexts determined from associated material
culture and 14 C assays. They are expressed in a conventional nomenclature for the sequence
of late prehistoric and historic cultures of the southern Levant (Stern et al., 2008). Specific
22

eferences to Early Bronze Age I and Iron Age contexts at the site of Megiddo are found in
two site reports by Finklestein et al. (2000; 2006). It was noted by Marco et al. (2006) that
the CF is the most plausible source of damage at Megiddo but they did not preclude the
DST as its source.
N
Jalame
Yoqneam
Shutter ridge
Figure 3: Morphotectonic mapping of displaced stream channels (marked with yellow circles) in a segment of
the CF between Jalame and Yoqneam. Dashed black lines indicate liniaments, which could indicate faults.
Modified after Ashkar et al. (2005) and presented on an aerial photograph.
23

GF
Earthquakes
2.0-2.9
3.0-3.9
4.0-4.9
5.0-5.9 Hall, 1996
Figure 4: Location of earthquake epicenters (M>2) in the vicinity of the CF system (white
rectangle) for the years 1980-2000 (Earthquake data from the Geophysical Institute of Israel).
Fault plain solution for the 5.3M earthquake of 1984 by Hofstetter et al., 1996.
24

Figure 5: Earthquakes for the years 1980-2007 along the CF and adjacent areas and the DST,
and their respective magnitude distribution, as reported by the Geophysical Institute of Israel.
Each point represents an earthquake.
1.4.2 Geological features of Denya neighborhood on Mount Carmel
The Denya neighborhood within the city of Haifa is situated on a spur sloping down
from the summit of Mt. Carmel in a westward direction towards Tirat Ha-Carmel, on the
south side of the mountain (Fig. 6). From the geological map drawn up by Karcz in 1958
(Fig.7), it can be seen that the neighborhood is located on an area where chalk and chert
rocks of the Shamir Formation (Upper Cenomanian) and limestones of the Mukhraka
Formation (Upper Cenomanian- Lower Turonian) are exposed. Denya Cave is situated at
(Map Ref. Israel Grid) 1487/2413, an area where Mukhraka limestone is exposed (Sass,
2007-personal communication; Fig. 7).
25

Denya Cave
Figure 6: Topographic map (1:50,000) of NW Mt. Carmel. Denya Cave (blue dot) is situated in
Denya Neighborhood on a spur sloping down to the town of Tirat Ha-Carmel along the Carmel
coast to the west.
26

15
30
Figure 7: Geological map of the northeastern side of Mt. Carmel (Karcz, 1958). The inset
indicates the location of Denya Cave, also marked by a blue dot. Two opposing dips, enhanced by
purple marks and numbered, were measured in the area around Denya Cave at a distance no
greater than 500m of each other. Green lines mark the locations of faults in the area of Denya
Cave, the dashed green line is an inferred fault.
Mediterranean Sea
Denya Fault
Denya Cave
Galim Fault
Figure 8: Part of a preliminary fault map of central and southern Mt.
Carmel (Segev and Sass, 2006).
27

According to Karcz (1958) there is a fault stretching from NW-SE along the upward
slope, east of Denya Cave (Fig. 7). It is estimated that displacement on this fault is less than
50m. North of the cave there is an inferred fault with a similar trend (Fig. 7). South of
Denya Cave a fault with an E-W direction is estimated by Karcz (1958) to have a throw of
50-150m (Fig. 7). In the area of exposed Mukhraka limestone the dips measured show two
different trends no more than 500m from each other (Fig. 7). Segev and Sass (2006) studied
the geology of the central and southern Carmel area and their preliminary fault map (Fig. 8)
defines two E-W trending faults in the area of Denya neighborhood; the Denya fault to the
north, along the northern slopes of the mountain spur (Fig. 6), which stretches to the east to
connect with the normal Galim fault to the south.
Circa 500m NW of the cave opening (Map Ref. Israel Grid 1485/2413) there is a
quarry where Mukhraka limestone is exposed and where a collapsed cave is quite evident,
and where speleothems can be seen (Fig. 9a,b). In that same spot there seems to be
evidence of faulting, while some of the limestone layers are tilted (~15° dip to NW; Fig.
9c). Furthermore, the collapsed cave seems to be situated on a fault plane.
Denya Cave is ca. 50m 2 in area with two main chambers. An upper chamber in which
speleothems are quite abundant is partitioned into three (Fig. 10). Throughout this chamber
evidence of collapses is seen in broken speleothems, fallen rocks and a tumbled segment of
a cave wall (Fig. 11). In a lower chamber chalk and cherts are exposed with some
speleothems found, predominantly below cracks (Fig 12). Cracks in the lower chamber
show an oblique displacement of a few centimeters (Fig.12d).
28

a
b
c
Figure 9: Pictures from a quarry in Denya neighborhood, Haifa (Map Ref. Israel Grid
1485/2413), ca. 500m from Denya Cave. a) Collaps formation along a fault strand. b) Exposed
speleothems, indicating the location of a collapsed cave. c) Limestone layers are tilted ~15° dip to
NW and evidence of faulting, which displaces chert lenses.
29

Entrance
A
B
C
Figure 10: Plan of upper chamber in Denya Cave, Haifa.
30

3
1
2
4
5
Figure 11: Seismic features in Denya Cave; 1) Collapsed wall segment. 2) Severed stalagmite.
3) An open crack. 4) Collapse cavity. 5) Broken stalactites.
a
b
c
d
Figure 12: Pictures from the lower chamber of Denya Cave; a) The lower chamber show
signs of incation (collapsed onto itself) exposing eroded chalk. b) Rock layers are horizontal,
indicating that there are no tilting movements. c) Widening crack in the chamber ceiling. d)
Cracks in the ceiling displace chert lenses and enable stalactite growth.
31

2. Research Objectives
The main objective of this study is to date paleo-earthquakes on the CF during the
Quaternary by means of damaged cave deposits.
Particular aims:
1. Dating collapses of speleothems by radiometric methods.
2. Establishing a viable connection between these collapse events and seismic events
during the Quaternary.
3. Exploring the connection between seismic ac<strong>tivity</strong> on the CF and the above
mentioned events in order to increase the paleoseismic data base for the CF
region.
4. Exploring the connection between the above mentioned events and the DST in
order to test the results of the main research objective.
3. Methodology
3.1 Mapping
Figure 10 is a plan of the chamber and the structural features that could indicate
seismic ac<strong>tivity</strong> within it in Denya Cave. This plan was drawn up in a two dimensional
method using the azimuth and distance of relevant points (samples, structural features and
chosen points along the cave walls) from a central location (sample DN-1). It proved to
be most accurate and useful for the purposes of this study.
Each speleothem sample was mapped and photographed and samples established as
probable seismites were marked (Fig. 10). All samples obtained are from the upper
chamber of Denya Cave. Speleothems in the lower chamber are not abundant and are
very hard to reach. Therefore, for the purpose of this study they were not sampled for
seismites.
3.2 Speleothem sampling
Speleothems assumed to be seismites were mapped, photographed and removed in as
complete a state as possible. Photographs of all Denya Cave samples along with detailed
descriptions and the location of each sample on the plan created of the upper chamber of
32

the cave can be viewed in Appendix I. At the Geological Survey of Israel (GSI) the
speleothems were sawed along their growth axes. The sections were photographed again
and the seismic contact or contacts identified. A seismic contact is defined as the
unconformity between what appears to be pre- and post-seismic laminae (Kagan et al.,
2005). Some speleothem samples were not seismites (Appendix I-I) while some yielded
indications of more than one seismic event (e.g. DN-33 Appendix I-II). The variety of
seismite samples required a means of classification, which was offered according to the
type of speleothem, the clarity of the seismic contact as a viable indicator for a seismic
event, and the ability to sample material (Fig. 13).
Where a seismic contact was identified, material was extracted from laminae located
as close as possible to it by a hand held pneumatic drill (e.g., Fig. 14). The last lamina
preceding the break event was termed a pre-seismic sample, while the first one to succeed
the break event was termed a post-seismic sample. The material was then analyzed using
the MC-ICP-MS, which enables dating of small amounts of material (~0.3g), and
therefore very accurate sampling of individual laminae. Where a seismic contact for
speleothems was determined, material was extracted from laminae located as close as
possible to the contact.
Most samples do not have either a pre- or a post- seismic phase of growth and so a
constraint on the age of the event is one sided. Such samples are, nevertheless, significant
if a number of them show similar ages, and more so if the same age is obtained from postand
pre-seismic samples (see ch. 4-Results).
33

Type A seismites show a clear break which
indicates an abrupt event where both pre and
post-break phases yield datable samples.
Type C seismites show a clear break which
indicates an abrupt event where only a pre-break
phase yields a datable sample.
A-1
Broken stalagmite with
a re-growth phase after
the break
C-1
Broken stalagmite in
which a pre-break sample
is dated
A-2
Broken stalactite with a
re-growth phase after
the break
C-2
Broken flowstone in
which a pre-break sample
is dated
A-3
Broken speleothem
covered by flowstone
C-3
Broken stalactite in which
a pre-break sample is
dated, which clearly
indicates a seismic event.
Type D seismites show fragments of un-datable
material embedded in flowstone which allows for
the dating of pre or post-break samples.
A-4
Broken flowstone
covered by unbroken
flowstone
D-1
Broken fragments embedded
on top of flowstone in which
a pre-break sample is datable
A-5
Broken speleothems
embedded in and
covered by flowstone
allowing for dating
samples of all the
phases prior and post
the break event
Type B seismites show a noticeable change in
sedimentation patterns which might be related to
an abrupt event where both pre and post break
phases yield datable samples.
B-1
Flowstone which shows a
distinct sedimentation
unconformity
D-2
Broken fragments below
flowstone in which a postbreak
sample is datable
Type E seismites show a clear break which
indicates an abrupt event where only a pre-break
phase yields a datable sample but are of
stalactites which as a rule are extremely fragile
and therefore could have broken at any recent,
non-seismic event. These samples, therefore, can
only be used as corroborative evidence if they
yield ages similar to those of other seismite types.
E-1
Broken stalactite in which a
pre-break sample is dated
B-2
Flowstone in which there
is an obstruction of
sedimentation by a phase
of broken fragments of undatable
material
Figure 13: Denya Cave seismite clasification. Red lines indicate seismic contac.
34

Figure 14: Sample DN-7
3.3 Dating of seismite samples
3.3.1 Multiple Collector Inductively Coupled Plasma Mass
Spectrometer
In this study dating with the U-series decay method was conducted using the MC-
ICP-MS (located at the geochemical laboratory of the Geological Survey of Israel in
Jerusalem), which measures Uranium and Thorium isotopes after chromatographic
separation from the calcite samples in the laboratory. The protocol for the
chromatographic separation of Uranium and Thorium from the calcite matrix is explained
in detail in Appendix II-I. These measurements are then used to calculate the isotopic
ratios needed for U-series age equations (see below).
35

3.3.2 Single sample dating
Single sample dating was done using equation [1] according to Broecker and
Kaufman (1965):
[1] [ 230 Th/ 234 U] = [ 238 U/ 234 U]*(1-e -λ230t ) + {1-[ 238 U/ 234 U]}*{λ 230 /(λ 230 -λ 234 )}*[1-e (-λ230-λ234)t ]
As mentioned above (ch. 1.3- Dating of speleothems), this equation is based on the
assumption that no initial 230 Th is present in the sample. Any initial 230 Th is always
accompanied by a much larger amount of 232 Th, therefore 232 Th is routinely monitored
during analysis, and samples containing less than an acceptable threshold of 230 Th/ 232 Th
can be identified (Hellstrom, 2007). According to Kaufman et al. (1998) a sample is
considered to have a high detrital content, which requires a correction for the contribution
of 230 Th by the decay of 232 Th, if this ratio is less than ~30, since for larger ratios the
correction becomes negligible compared to the analytical uncertainty. Richards and
Dorale (2003) and Li et al. (1989) argued that thresholds of between 100 and 300 for the
case of mass spectrometric dating, due to the high-precision analysis of initial 230 Th.
Hellstrom (2007) argued that even a value of 230 Th/ 232 Th=300 requires a correction for
the derital fraction.
Considering these higher values, most ages obtained for Denya Cave seismite samples
need to be corrected for initial 230 Th, using as a correction factor the detrital molar ratio of
232 Th/ 238 U. The most common correction factor for crust value rocks is 3.8 (Wedepohl,
1995). Even higher values of 4.2 were determined (e.g. Kuperman, 2005). Haase-
Schramm et al. (2003) reported a single sample correction factor for Lake Lisan
aragonites detritus of 232 Th/ 238 U atomic ratio=0.85 (i.e. 232 Th/ 238 U detrital molar ratio of
0.83=0.27 ac<strong>tivity</strong> ratio*3.05). They also suggested that some initial 230 Th found in those
samples was contributed by hydrogenous Th. In a carbonate terrain the correction factor
was calculated by Kaufman et al. (1998), using an isochron method, yielding a value of
1.8±0.25=detrital molar ratio (Soreq cave). In their study Kaufman et al. (1998) showed
that all the Th in the speleothems from Soreq cave was associated with detrital material.
In their method the slopes of isochrons in a plot of ( 232 Th/ 234 U) vs. ( 230 Th/ 234 U) were used
in order to calculate the detrital molar ratio of 232 Th/ 238 U. Those isochron lines are
essentially mixing lines between a clean sample (low detrital component) and the DEM
within the lamina, since stalagmites often have observable differences in the quantity of
detrital material along growth layers (Richards and Dorale, 2003). Following Kaufman et
al. (1998) isochron slopes and their intersects with the Y axis ( 230 Th/ 234 U) enables a
calculation of a correction factor as follows:
36

[3] ( 230 Th)/( 232 Th) d = ( 234 U)/( 232 Th) d = Isochron Slope/(1-Isochron Y axis intersect)
[4] ( 232 Th)/( 238 U) d = {1/( 230 Th)/( 232 Th) d } x 3.049
d- value of the DEM in the sample.
Isochron slope and Y axis intersect were calculated using Isoplot3.7, in which errors
are considered for regression line calculations (Tables 1b, 2b, 3b).
3.049- constant value for the transferring ac<strong>tivity</strong> ratios to molar ratios.
This method was applied to four laminae from Denya Cave speleothems, from which
between four and five samples were drilled and dated in order to plot along the above
mentioned isochron line (Fig. 15). After dissolving the samples with HNO 3 no insoluble
matter remained and most yielded 230 Th/ 232 Th ac<strong>tivity</strong> ratios higher than ~100, however,
some speleothems also had lower values (i.e. between ~30 and ~100) (Table 1a). Their
calculated ac<strong>tivity</strong> ratios of 232 Th/ 234 U and 230 Th/ 234 U were plotted along isochron lines
(Table 1a,b). Those isochrons yielded an average correction factor of less than 0.2 (Table
1b). This value is much lower than the one calculated for Soreq Cave (Kaufman et al.,
1998) or even Lake Lisan (Haase-Schramm et al., 2003). Using this value means that a
correction of measured ages is extremely high for Denya Cave. There was no reason to
believe that for samples with no detritus, such a correction should be applied. It is
therefore suggested that these related low 230 Th/ 232 Th ratios were not caused by detrital
matter in the samples used for isochrons, since such samples cannot yield a correction
factor for detrital Th if they contain no detritus, and that the source for initial 230 Th is not
solely from detrital material.
Another attempt at establishing a correction factor for Denya Cave was made by
taking four samples, which after dissolution had large amounts of detritic matter. Between
four and five samples from each lamina were drilled and dated (Fig. 16 and Table 2a). All
of these samples yielded 230 Th/ 232 Th calculated values of between ~60 to less than ~20.
The average correction factor calculated for these isochron samples was ~0.6 (Table 2b).
Those samples were taken from laminae that are close to the surfaces of speleothem
samples (Fig. 16). Results indicate that once the sample contains a higher detrital fraction,
the correction factor is lower than for samples with lower detrital content. Yet, both
correction factors are still much lower than the factors for crustal rocks or carbonate
rocks. This suggests that the origin of initial 230 Th in the speleothems is not only
contributed by detrital matter but also from another source (possibly hydrogenous).
Dated samples from pre- and post-seismic event laminae of seismite samples were
also used as isochrons assuming they are very close in age (i.e. DN-4 pre samples, DN-6c
37

pre samples, DN-7 post samples and DN-9 pre samples- photographic view in Appendix
I-II). Those samples yielded 230 Th/ 232 Th calculated values between ~200 and ~2 (Table
3a). The correction factors established from these samples varied between ~0.08 and
~0.19 for five different calculations, yielding an average value of ~0.7 (Table 3b). These
values are similar to the values obtained from detritus-rich speleothem isochron samples.
These three attempts of creating isochron plots in order to obtain correction values
clearly show the complex nature of detrital matter within them. The most likely cause of
scatter in isochrons is not the sampling methodology used in this study, but a combination
of more than one source of initial Th; (1) detrital Th, (2) hydrogenous Th adsorbed to
detritus and oxides (3) hydrogenous Th directly incorporated by carbonates (Richards and
Dorale, 2003 and references therein). Different sources of initial Th may explain the
scattered isochrons demonstrated in Tables 1b, 2b and 3b.
There are several processes which may explain various Th sources in speleothems.
During a depositional hiatus the outer lamina of a speleothem is exposed to the cave
environment for an extended amount of time, allowing detrital matter to settle on it.
Consequently, that lamina may contain a large amount of detrital Th. These hiatuses
could potentially be the result of a change in hydrological settings in a karstic cave due to
seismic events. Such changes in hydrological settings might also allow for an
incorporation of hydrogenous Th into the cave system. Furthermore, when a cave
undergoes an earthquake event, detrital material might rise up from the cave's walls and
floor due to collapses, or it might enter more readily from the surface due to openings of
cracks and ground shaking. This material may embed itself within the outer or broken
laminae of speleothems. It is therefore not surprising that some seismite samples appear
to have a higher detrital content than the underlying laminae of the same speleothems.
This however, is not the case with all seismite samples from Denya Cave, which do not
all contain a noticeable amount of detrital matter (Table 4). It is therefore likely that the
amount and composition of detrital material in seismite samples varies quite significantly
and that no single correction value can be found for these samples.
The above mentioned correction values were deemed unusable for Denya Cave
speleo-seismite age corrections, since the variations in factors are too great in such low
values as to enable the use of an average factor. When applied, they make an extremely
significant difference to most of the calculated ages obtained in Denya Cave, making it
crucial to be more accurate. Moreover, accurate calculations of the slopes and y-intersects
of the isochrons, using the errors of the isotopic ratios (with Isoplot3.7), yielded
38

extremely high errors for these values and make any calculation for a correction factor
highly suspicious (Tables 1b,2b,3b). Since these correction factors vary between samples
with high detrital contents (i.e. 230 Th/ 232 Th 100), it is possible that it is not indicative of a single phase or origin of
detrital matter. It was therefore not possible to establish a unique correction factor for
Denya Cave initial 230 Th.
39

Iso-III
Iso-IV
Iso-II
Iso-I
Det-I
Det-II
Iso2-IV
Iso-IV
Iso-III
Iso-II
Iso-I
Det-II
Iso2-III
Iso2-II
Iso2-I
Iso-V
Det-III
Det-I
Figure 15: Photographic ilustration of the location of drilling for
isochron samples: DN-4 Iso, DN-4 Iso2 and DN-17 Iso (marked
in red). Detritus samples for experiment with detrital matter are
marked in black (results in Table 4).
Table 1: Isochron sample's results of low detrital content samples: a. Calculated isotopic
ratios and ages. b. Calculated slopes and y-axis intercepts for correction factor
calculations. Isochron plot: red-DN-4 Iso, green-DN-4 Iso 2, blue-DN-17 Iso. Unreliable
results are marked in orange.
a
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN-4-ISO-I 0.27946 0.00251 3.57836 0.03210 0.001275 0.000002 219.25 1.99 35480 377 377
DN-4-ISO-II 0.28716 0.00344 3.48239 0.04170 0.001146 0.000002 250.58 3.06 36661 525 522
DN-4-ISO-III 0.28202 0.00284 3.54583 0.03565 0.001321 0.000001 213.56 2.35 35892 429 427
DN-4-ISO-IV 0.28937 0.00234 3.45584 0.02791 0.001006 0.000001 287.64 2.40 37004 357 357
DN-4-ISO-V 0.39892 0.01180 2.50676 0.07417 0.007947 0.000018 50.20 1.51 55006 2136 2096
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN-4-ISO2-I 0.26888 0.00693 3.71919 0.09587 0.000581 0.000001 462.74 13.47 33953 1031 1022
DN-4-ISO2-II 0.29913 0.00412 3.34303 0.04609 0.001058 0.000002 282.82 4.42 38495 640 636
DN-4-ISO2-III 0.28498 0.00383 3.50900 0.04712 0.000810 0.000001 351.97 5.06 36336 582 578
DN-4-ISO2-IV 0.30430 0.00456 3.28620 0.04926 0.003117 0.000005 97.64 1.64 39280 713 707
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN-17 preIso 0.37245 0.00819 2.68493 0.05901 0.002773 0.000004 134.30 3.37 50381 1417 1399
DN-17-ISO-I 0.39978 0.00867 2.50139 0.05424 0.012714 0.000021 31.44 0.71 55208 1571 1548
DN-17-ISO-II 0.31416 0.00430 3.18309 0.04356 0.002171 0.000007 144.69 2.15 40823 687 681
DN-17-ISO-III 0.35639 0.00610 2.80588 0.04806 0.005250 0.000008 67.88 1.26 47667 1029 1020
DN-17-ISO-IV 0.42662 0.01077 2.34403 0.05918 0.009889 0.000018 43.14 1.15 60090 2041 2004
DN-17 postIso 0.30416 0.00160 3.28769 0.01731 0.004288 0.000007 70.94 0.42 39269 250 250
b
DN-4 Iso Slope ± Intersect ± 230/232d 232/238d Av. 232/238d
All 17 3.6 0.264 0.013 23.09783 0.132004 0.156161723
I-IV -29.6 10 0.3193 0.012 -43.48465 -0.070117
DN-4 Iso2 Slope ± Intersect ± 230/232d 232/238d
All 16 38 0.267 0.062 21.8281 0.139682
I-III 61.7 15 0.2343 0.014 80.57986 0.037838
DN-17 Iso Slope ± Intersect ± 230/232d 232/238d
All 11 16 0.29 0.13 15.49296 0.196799
230 Th/
234 U
0.44
0.40
0.36
0.32
data-point error crosses are 2σ
0.28
0.24
0.000 0.002 0.004 0.006 0.008 0.010 0.012 0.014
232 Th/ 234 U
40

DN-62
Iso-III
Iso-II
Iso-I
Iso-V
Iso-I
Iso-II
DN-35
Iso-III
Iso-IV
Iso-IV
Iso-I Iso-II Iso-III
Iso-IV
Iso-I
Iso-II
Iso-III
Iso-IV
Iso-V
DN-53
Figure 16: Photographic ilustration of the location of drilling for isochron samples: DN-16 Iso,
DN-35 Iso, DN-53 Iso and DN-62 Iso.
Table 2: Isochron sample's results of low detrital content samples: a. Calculated isotopic ratios and
ages. b. Calculated slopes and y-axis intercepts for correction factor calculations. Isochron plot:
red-DN-16 Iso, green-DN-53 Iso, blue-DN-35 Iso, yellow-DN-62. Unreliable results are marked in
orange.
a
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN-16 Iso-I 0.59594 0.00665 1.67803 0.01873 0.043332 0.000079 13.75 0.16 97634 1804 1773
DN-16 Iso-II 0.72886 0.01116 1.37201 0.02101 0.062474 0.000214 11.67 0.21 138980 4394 4223
DN-16 Iso-III 0.55393 0.00855 1.80529 0.02786 0.023816 0.000049 23.26 0.37 86939 2084 2044
DN-16 Iso-IV 0.50820 0.02346 1.96772 0.09084 0.009353 0.000022 54.33 2.67 76480 5215 4978
DN-16 Iso-V 0.53010 0.00906 1.88644 0.03225 0.012159 0.000020 43.60 0.80 81325 2102 2061
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN-35 Iso-I 0.28868 0.00512 3.46406 0.06147 0.027135 0.000054 10.64 0.20 36913 784 778
DN-35 Iso-II 0.25748 0.00182 3.88376 0.02751 0.139039 0.000198 1.85 0.01 32256 267 267
DN-35 Iso-III 0.25392 0.00167 3.93830 0.02596 0.016835 0.000045 15.08 0.10 31745 245 244
DN-35 Iso-IV 0.53010 0.00906 1.88644 0.03225 0.012159 0.000021 43.60 0.80 81325 2102 2061
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN-53 Iso-I 0.34136 0.00188 2.92947 0.01616 0.049020 0.000059 6.96 0.04 45334 314 314
DN-53 Iso-II 0.34546 0.00134 2.89472 0.01120 0.022362 0.000023 15.45 0.07 45866 225 225
DN-53 Iso-III 0.33195 0.00380 3.01252 0.03444 0.018581 0.000016 17.87 0.21 43664 619 615
DN-53 Iso-IV 0.28812 0.00216 3.47084 0.02603 0.017057 0.000024 16.89 0.12 36822 332 332
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN-62 Iso-I 0.29858 0.00230 3.34923 0.02577 0.023897 0.000064 12.49 0.10 38420 358 358
DN-62 Iso-II 0.31629 0.00264 3.16167 0.02643 0.023659 0.000043 13.37 0.11 41170 423 421
DN-62 Iso-III 0.32765 0.00303 3.05200 0.02824 0.030905 0.000028 10.60 0.10 43002 491 489
DN-62 Iso-IV 0.24866 0.00240 4.02156 0.03883 0.012956 0.000032 19.19 0.19 30985 346 346
DN-62 Iso-V 0.30091 0.00237 3.32323 0.02613 0.023423 0.000047 12.85 0.11 38777 366 366
b
DN-16 Iso Slope ± Intersect ± 230/232d 232/238d Av. 232/238d
All 3.9 2 0.465 0.071 7.28972 0.41826 0.606166325
I, III-V 2.18 0.32 0.5016 0.01 4.373997 0.697074
DN-53 Iso Slope ± Intersept ± 230/232d 232/238d
All 3 16 0.24 0.44 3.947368 0.772413
I-III 1 43 0.3 1.3 1.428571 2.1343
DN-62 Iso Slope ± Intersept ± 230/232d 232/238d
All 4.7 2.5 0.19 0.06 5.802469 0.525466
I-III,V 3.9 7.7 0.21 0.2 4.936709 0.617618
DN-35 Iso Slope ± Intersect ± 230/232d 232/238d
All -5 31 0.6 1.7 -12.5 -0.24392
I-III -1 28 0.3 1.8 -1.428571 -2.1343
230 Th/
234 U
0.7
0.6
0.5
0.4
0.3
data-point error crosses are 2σ
0.2
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14
232 Th/ 234 U
41

Table 3: Isochron sample's results of low detrital content samples: a. Calculated isotopic ratios
and ages. b. Calculated slopes and y-axis intercepts for correction factor calculations. Isochron
plot: yellow-DN-4 pre, red-DN-6c pre, green-DN-7 pre, blue-DN-7 post. Unreliable results are
marked in orange.
a
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN-4 pre (top) 0.14265 0.00169 7.01033 0.08305 0.013535 0.000016 10.54 0.13 16717 214 214
DN-4 pre II (post) 0.16915 0.00276 5.91195 0.09649 0.025442 0.000032 6.65 0.11 20132 362 361
DN 4 pre 0.16814 0.00134 5.94752 0.04748 0.001572 0.000002 106.97 0.87 19981 175 175
DN3y(dn4-pre) 0.20100 0.00267 4.97501 0.06616 0.006784 0.000008 29.63 0.41 24343 364 362
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN8y(dn6C pre) 0.14291 0.00280 6.99729 0.13702 0.023083 0.000026 6.19 0.12 16749 355 354
DN7y(dn6C pre) 0.28225 0.00319 3.54296 0.04006 0.001928 0.000003 146.36 1.67 35921 483 481
DN 6C pre 0.27134 0.00237 3.68536 0.03222 0.001525 0.000001 177.99 1.57 34300 352 352
DN-6c pre I 0.18607 0.00207 5.37436 0.05989 0.019748 0.000027 9.42 0.11 22317 276 276
DN-6c pre II 0.27851 0.00236 3.59048 0.03039 0.003278 0.000005 84.97 0.78 35363 354 354
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN 7 pre 0.20218 0.00145 4.94600 0.03553 0.010228 0.000011 19.77 0.15 24511 198 198
DN-7-45 0.26418 0.00166 3.78527 0.02379 0.010182 0.000014 25.95 0.17 33202 245 245
DN-7-43 0.29038 0.00254 3.44376 0.03012 0.001742 0.000002 166.70 1.50 37142 389 388
DN-7-44 0.28619 0.00171 3.49419 0.02083 0.001982 0.000004 144.37 0.86 36515 262 262
Sample name 230/234 err 234/230 err 232/234 err 230/232 err Age(y) + -
DN 7 post 0.10624 0.00123 9.41238 0.10919 0.007832 0.000008 13.56 0.16 12206 150 150
DN 7postB 0.09668 0.00067 10.34369 0.07126 0.007685 0.000008 12.58 0.09 11050 80 80
DN-7-46 0.10627 0.00134 9.40958 0.11876 0.004735 0.000007 22.44 0.29 12208 163 163
DN-7-46b-post 0.08100 0.00166 12.34566 0.25263 0.002975 0.000006 27.23 0.56 9181 196 196
DN-7-47 0.09181 0.00134 10.89230 0.15885 0.002397 0.000002 38.30 0.56 10464 160 160
b
DN-4 pre Slope ± Intersect ± 230/232d 232/238d Av. 232/238d
all -8 82 0.27 0.99 -10.9589 -0.278221 0.076689247
No DN3y 31 9700 0 130 31 0.098355
DN-6c Slope ± Intersect ± 230/232d 232/238d
all -6 1.8 0.292 0.025 -8.474576 -0.359782
partI -5.2 2.4 0.289 0.025 -7.313643 -0.416892
partII 12 310 0.25 0.69 16 0.190563
DN-7 pre Slope ± Intersect ± 230/232d 232/238d
all 174 430 2.9 3 -91.57895 -0.033294
DN-7 post Slope ± Intersect ± 230/232d 232/238d
all 6 12 0.066 0.067 6.423983 0.009531
230 Th/
234 U
0.30
0.26
0.22
0.18
0.14
0.10
data-point error crosses are 2σ
No-47 7 26 0.05 0.16 7.368421 0.008309 0.06
0.00 0.04
232 Th/ 234 U
In order to determine the nature of the detrital component found in samples from
Denya Cave and to establish its origin, four different speleothem samples were dissolved
with two different methods. Part of the sample was dissolved with weak acetic acid,
which only dissolves the carbonate component and does not affect the clays, and the other
underwent total dissolution with HNO 3 and HF (see Appendix II-I,II). The samples that
were treated with acetic acid were then placed in a centrifuge, which enabled the
separation of all insoluble matter (Appendix II-I,II). A comparison of 230 Th/ 232 Th ratios
between the two methods can be seen in Table 4. Three observations can be discerned
from the results of this experiment; (1) 230 Th/ 232 Th is quite low (

contribution of 232 Th carried by detrital matter in Denya Cave samples. The carbonate
fraction of the samples most probably carries hydrogenous 232 Th. It is possible that this
hydrogenous 232 Th does not overly contribute to the abundance of 230 Th because it is not
as old as 232 Th carried in clays, and therefore does not affect the age of the sample. Under
this assumption an attempt to find a correction factor for each of the detrital samples was
made, in order to correct their ages to that of the samples, which do not contain a detrital
component. As can be seen in Table 4b, two of the samples yielded the same ages as their
detrital free counterparts when a correction factor of ~0.4 was applied (DN-4 pre top and
DN-14a pre). Sample [DN-4 pre II] did not need a correction factor at all. Sample [DN-
37a post] is much older than its detrital free counterpart and a significant correction was
needed in order for them to be of the same age, yet once a correction factor lower than 0.6
was applied the calculated ages were negative. This might mean that theoretically the
factor should be ~0.4 yet there is no way to validate this assumption. These results
indicate that an age correction is not always necessary, even when 230 Th/ 232 Th ratios in
samples are low. However, a correction cannot be arbitrarily neglected and therefore the
single sample method of dating is not appropriate for speleo-seismites from Denya Cave.
Another approach to establishing the real ages of Denya Cave seismite samples was
the Osmond isochron method modified by Ludwig and Titterington (1994; see below).
43

Table 4: Results of an experiment in order to determine the nature of the detrital component found in samples from Denya Cave.
Sample name DN-4top det.carb DN-4 pre (top) DN-4 pre II det.carb. DN-4 pre II det. DN-14a pre dert.carb DN-14a pre det. DN-37a post det.carb. DN-37a post det.
238U ppm 0.2565 0.2380 0.2636 0.2529 0.2172 0.2245 0.2925
0.4672
err 0.00012 0.00012 0.00025 0.00031 0.00015 0.00025 0.00026 0.00036
234/238 1.0570 1.0512 1.0752 1.0754 1.0787 1.0632 1.0966 0.8770
err 0.00153 0.00122 0.00139 0.00229 0.00177 0.00280 0.00174 0.00137
234U ppm 1.45838E-05 1.346E-05 1.52438E-05 1.46304E-05 1.26048E-05 1.2838E-05 1.72529E-05 2.20431E-05
err 2.11285E-08 1.55631E-08 1.97779E-08 3.121E-08 2.06263E-08 3.37751E-08 2.73144E-08 3.4502E-08
230Th ppb 0.00020 0.00058 0.00075 0.00068 0.00086 0.00130 0.00060 0.00544
err 3.74357E-06 6.86007E-06 3.13787E-06 1.87992E-06 4.55549E-06 4.9666E-06 2.73174E-06 1.5893E-05
232Th ppb 3.1085 10.6792 3.5884 3.9056 6.2344 12.8180 8.2122 194.2430
err 0.00929 0.02735 0.00532 0.00604 0.01012 0.02310 0.00993 0.36148
230/232 12.80 10.54 39.49 33.05 26.04 19.14 13.91 5.26
err 0.24 0.13 0.18 0.10 0.14 0.08 0.07 0.02
230/234 0.0454 0.1426 0.1624 0.1538 0.2239 0.3333 0.1151 0.8145
err 0.00085 0.00169 0.00071 0.00054 0.00125 0.00155 0.00055 0.00270
234/230 22.0169 7.0103 6.1576 6.5033 4.4658 2.9999 8.6904 1.2277
err 0.41185 0.08305 0.02697 0.02267 0.02488 0.01394 0.04179 0.00407
234/232 281.7367 73.8841 243.1749 214.9333 116.2839 57.4280 120.9191 6.4609
err 0.41068 0.08591 0.31604 0.45902 0.19059 0.15127 0.19161 0.01013
238/232 250.3183 67.6223 222.8317 196.4514 105.7076 53.1291 108.0534 7.2977
err 0.75715 0.17667 0.39297 0.38883 0.18727 0.11256 0.16233 0.01469
Age(y) 5053 16717 19233 18123 27483 43903 13272
201137
+ 97 214 93 70 175 258 68
2405
- -97 -214 -93 -70 -175 -258 -68
-2337
232/238 detr mol ratio 0.43 0.4 0.60
Equiv (230/232) 7.29168 7.83855 5.22570
detrital fraction 0.10705 0.14646 0.71087
(234/238) corr 1.05733 1.07403 0.57465
err 0.00122 0.00283 0.00090
(230/234) corr 0.04544 0.22683 0.02097
err 0.00054 0.00105 0.00007
Corrected age (y) 5117 27892 2324

3.3.3 Cluster dating
Osmond isochron dating is based equation [2] according to Broecker (1963):
[2] [ 230 Th/ 238 U] = (1-e -λ230t ) + {[ 238 U/ 234 U] - 1}*{λ 230 /(λ 230 -λ 234 )}*[1-e -(λ230-λ234)t ]
The calculation of age is done using Isoplot3.7 (Ludwig, 2008) with a first derivative
estimation for samples of similar ages plotted on isochron lines (sample age clusters)
Here too the analytical error (±2σ) is given.
The Isoplot program creates a three dimensional plot where x= 230 Th/ 238 U, y= 234 U/ 238 U
and z= 232 Th/ 238 U. This plot, based on the U-series evolution diagram of 230 Th/ 238 U vs.
234 U/ 238 U, incorporates the detrital end member (DEM) of the dated sample and using the
z-axis corrects for it and calculates an average age for all samples plotted on the isochron
line (Ludwig and Titterington, 1994).
Age clusters were determined for the seismite samples, which were then plotted on an
isochron line. These clusters are derived from the ages of seismites from the cave, which
tended to cluster at very specific intervals, as well as from criteria based on the amount of
detrital matter within the dated sample, structural features within the cave and
stratigraphic considerations in the sample laminae.
Criteria for establishing a reasonable isochron plot are as follows: Foremost is the
relationship between samples within speleothems. When dated samples came from the
same lamina, and yet yielded varying ages because of the varying amounts of detrital
matter which they contain, they were considered as being of the same age. Another
consideration takes into account the very high detrital content in a few of the samples
observed during analysis. This indicated that they might plot on an isochron plot of
younger ages. When the sample added to the accuracy of the plot and consequently the
age it yielded, it was considered an indication that the correction the program gave for its
age was valid.
An important aspect of determining ages of seismic events is based on the types of
seismites representing it (Table 5), as well as on their locations within the cave (Fig. 10).
If all seismite samples of age clusters were found in the same place in the cave, they
might indicate a localized breaking event that might not be seismic in origin. By the same
token, seismites of the same age, which are located in different parts of the cave,
represent an event which affected the whole cave and is, therefore, most likely seismic in
origin.
45

A significant observation of some seismite samples showed a low 230 Th/ 232 Th ac<strong>tivity</strong>
value (

4. Results
A total of 68 speleothem samples was taken and inspected from Denya Cave, 37 of
which were identified as seismites (Appendix I). 32 seismites were processed for dating
(Table 5). Some show evidence of more than one seismic event or have indications of
both pre- and post-seismic events. Ten seismites are severed stalagmites broken along sub
horizontal plains, as are some described by Forti and Postpitchl (1980). These ten
stalagmites vary in sizes and shapes and are not all broken at their bases, as Lacave et al.
(2000) and Gilli et al. (1999) assumed they would be due to the heterogeneity of their
structures. This could indicate a great complexity in the earthquake induced break
mechanisms which occur in cave environments. Nine seismites of the 32 are severed
stalactites in different shapes and sizes. Such seismites have been recorded in many caves
after recent earthquakes (e.g. Gilli et al., 1999; Aydan, 2008). The remainders of the
seismites are flowstone samples in which breaks and depositional unconformities were
found; some revealed embedded soda straw speleothems.
4.1 Single sample age analysis
Each seismite sample was drawn and classified according to its structure and type of
break (Table 5 and photographic view in Appendix I-II).
All samples of what appeared to be pre- and post-seismic events were dated with the
U-Th method, using equation [1] according to Broeker and Kaufman (1965) (Table 6). As
aforementioned, the samples were taken from laminae closest to the seismic contact (see
ch. 3.2- Speleothem sampling), allowing for the closest age constraint to a seismic event.
Each pre-seismite single sample age (marked in red- Table 6) potentially indicates the
time at which the speleothem broke or in some cases (e.g. DN-48, Appendix I-II) abruptly
changed its growth pattern due to a seismic event. Each post-seismite single sample age
(marked in black- Table 6) potentially indicates the time of a speleothem re-growth, either
right after a seismic event, which broke a speleothem, or due to a seismic event, which
created a change in the hydrological setting in the cave. When pre and post dated samples
of the same seismite in a speleothem have very close ages, and are not reversed in order
(stratigraphically plausible), they could very well indicate the precise time of a seismic
event. Other potential pairs have a long hiatus of deposition between them and can only
indicate a one sided constraint on the age of a seismic event along with un-paired
samples. Figure 17 illustrates the ages of each dated sample within the speleothem
47

seismites, and the relationships between them (hiatus within each event are marked by a
dashed line). This figure illustrates relations between dated samples in speleothems as
well as a sense of the degree to which the samples cluster at specific ages. A cluster of
such ages indicates a seismic event which caused damage to more than one speleothem
and is therefore statistically more reliable than that indicated by just one or two seismites.
Examining the record of the last 200ka was an attempt to determine whether the dated
samples cluster around specific ages in order to estimate when seismic events occurred. A
plot stacking samples of approximately the same age (including their error margins) one
on top of the other can show peaks where ages cluster. Using the sample types noted in
Table 5, each sample was qualified according to its type. Since some samples are more
obviously seismites than others, they were ranked accordingly. Type A samples received
a ranking of five, while Types B, C, D and E were ranked 4, 3, 2 and 1 respectively (Fig.
18). The higher the ranking number the greater likelihood of the sample being a seismite.
The value of each sample in this stacking plot was multiplied by its factor and the ranked
value then placed on the plot (Fig. 18), indicating peaks at specific ages associated with
seismic events. Some seismite samples were dated more than once (i.e. seismite samples
used for isochron calculations. See Table 3). Those samples would cause biased peaks in
this kind of plot because they would multiply the amount of samples stacked at a specific
age. Since the ages determined from single samples were not corrected (see ch. 3.3.2-
Single sample dating), and there was no way to determine their real age, an average age
was applied for such samples. The lack of certainty of the corrected ages also means that
it is not clear what the correct ages of the clusters are, and whether certain samples should
actually be part of a different cluster since its true age should be younger due to high
detrital component. Nevertheless, Figure 18 clearly indicates that groups of speleothems
were damaged at specific times (i.e. ca. 29ka, 39ka, 43ka, 56ka, 138ka and 149ka). Some
sample clusters may be inferred from groups of close ages (i.e. ca. 6-8ka, 11-12ka, 14-
16ka, 19-22ka, and 25ka), considering the error of the ages and the detrital factor in some
of the samples, which may reduce their ages (indicated by low 230 Th/ 232 Th ratios in Table
6).
48

Table 5: Denya Cave seismite I.D.'s
Sample name Description Dated sample
Type
(Fig. 13-17)
DEN-2 broken stalagmite DEN-2 pre C-1
DN-2 broken stalagmite DN-2-1
DN-2-2
DN-2-3
DN-2-4 A-1
DN-4 broken stalagmite DN-4 pre (top)
DN-4-pre I
DN 4 pre II
DN-4 pre III (post) C-1
DN-6 flowstone on fallen rock DN-6a pre (post) C-3
stalactite on fallen rock DN-6b pre C-3
stalactite on fallen rock DN-6c pre
DN-6c pre
DN 6c pre
DN-6c pre I
DN-6c pre II C-3
DN-7 broken stalagmite DN-7 pre
DN-7 post
DN-7postb
DN-7-45 (pre)
DN-7-46 (post)
DN-7-46b (post)
DN-7-47 (post) A-1
DN-9 broken stalagmite DN-9b pre (down)
DN-9b pre (bottom)
DN-9b pre (bottom)(post)
DN 9b pre C-1
DN-14 broken stalagmite DN-14a pre I
DN-14a PRE-I C-1
DN-17 broken stalagmite DN-17 pre
DN-17 post A-1
DN-19 broken stalagmite DN-19 pre I
DN-19 pre II C-1
DN-21 broken stalagmite DN-21pre I
DN-21 pre II C-1
DN-22 flowstone core DN-22 pre I
DN-22 pre II
DN-22 post I
DN-22 post II A-4
DN-25 flowstone cover DN-25 post I
DN-25 post II D-2
DN-26
DN-26 top-pre I
DN-26 top-post I A-4
DN-27 flowstone cover DN-27 post II D-2
DN-33 broken stalactite DN-33c1 pre
DN-33c1 post
DN-33c2 pre
DN-33c2 post A-2
49

Table 1- continuation
DN-34 flowstone core DN-34a pre I
DN-34a pre II
DN-34a pre III
DN-34a post A-5
DN-36 flowstone core DN-36 pre I
DN-36 post I A-4
DN-36 pre II
DN-36 post II A-5
DN-36 pre III E-1
DN-37 flowstone core DN-37a pre D-1
DN-37a post D-2
DN-40 cracked flowstone DN-40-pre I
DN-40-post I B-2
DN-40-pre II C-1
DN-42 stalactite & stalagmite DN-42e-pre
DN-42e-post A-2
DN-44 flowstone core DN-44 pre
DN-44 post A-4
DN-45 broken stalagmite DN-45 pre
DN-45 post A-1
DN-46 flowstone core DN-46 pre I
DN-46 pre II
DN-46 post A-3
DN-47 flowstone core DN-47 pre I
DN-47 post I A-4
DN-47 pre II (seis.) E-1
DN-48 flowstone core DN-48 pre
DN-48 post B-1
DN-51 broken stalactites on f.s. DN-51 pre I A-4
DN-51 pre II
DN-51 pre III
DN-51 pre IV
DN-51 post I E-1
DN-52 flowstone core DN-52 pre
DN-52 post A-3
DN-62 flowstone DN-62 pre I
DN-62 post I A-4
DN-62 post II D-2
DN-63 cracked flowstone DN-63 pre I
DN-63 pre II
DN-63 post A-5
DN-65 flowstone + bedrock DN-65 pre
DN-65 post A-4
DN-66 stalagmites & stalactites DN-66b pre E-1
DN-66c pre I
Dn-66c post I A-2
DN-66c pre II
DN-66c post II A-2
DN-66c pre III E-1
DN-68 broken stalagmite DN-68 pre C-1
50

Figure 17: Dated seismite uncorrected ages. Red dots signify pre-seismic event samples and black
indicate post-seismic event samples. Dashed lines indicate the hiatus of deposition between
connected samples. Green frames indicate where samples may cluster around specific ages, when
considering the error margin of the ages and the detrital component, which is present in some
samples (see. Table 6) and may reduce their age. Green circles indicate sample pairs that have a
minimal hiatus between the pre- and post-seismic event dated samples. Data for this plot may be
found in Appendix III.
51

(Number of samples) x (Quality of samples)
Age (ka)
(Number of samples) x (Quality of samples)
Age (ka)
Figure 18: Sample stacking plot; each sample is stacked on top of the samples with the same age to
show a peak where ages cluster. Samples of a type A, B, C, D and E were multiplied by factors of 5, 4,
3, 2 and 1 respectively to show the quality of the age cluster. The plot is based on sample’s
uncorrected ages and since some of the samples contain detrital Th their age should be corrected,
putting them in other age clusters or creating different age clusters altogether. The large purple
circles indicate clearly visible peaks and the small circles indicate ages of sample clusters within the
error margin or accounting for the detrital component, which is present in some samples (indicated
by low 230 Th/ 232 Th ratios in Table 6).
52

Table 6: Dated seismite samples' isotopic ratios and uncorrected ages. Samples are arranged by
age for Isochron calculations. Red samples are pre-seismic event and black samples are postseismic
event. The detrital component of samples was established in the lab for most samples.
Markings in blue are for samples that were established in the lab ex post facto as near as possible
to the original sample. For all ac<strong>tivity</strong> ratios obtained for these samples see Appendix IV.
Dated sample name 234/238 err 230/234 err 230/238 err 232/238 err 230/232 err Det. Age (y) + -
DN-33c1-post 1.06245 0.00216 0.00428 0.00009 0.00454 0.00010 0.001112 0.000003 5.61 0.12 n 466 10 -10
DN-42e-post 1.05686 0.00153 0.00708 0.00028 0.00749 0.00030 0.000517 0.000002 17.52 0.70 n 773 31 -31
DN-51 pre III 1.04455 0.00108 0.04394 0.00116 0.04590 0.00121 0.004875 0.000019 10.15 0.27 y 4886 131 -131
DN-2-3 1.04588 0.00237 0.04755 0.00220 0.04973 0.00230 0.002880 0.000022 22.50 1.05 n 5296 250 -250
DN-2-4 1.04588 0.00152 0.05618 0.00197 0.05875 0.00206 0.004098 0.000024 16.88 0.60 y 6285 227 -227
DN-51 pre II 0.99870 0.01697 0.07354 0.00230 0.07344 0.00261 0.011608 0.000087 6.63 0.18 y 8307 271 -271
DN-66c-pre III 1.05658 0.00100 0.07948 0.00183 0.08397 0.00193 0.038891 0.000187 1.93 0.05 y 9000 1495 -1475
DN-7-46b-post 1.04368 0.00212 0.08100 0.00166 0.08454 0.00174 0.003445 0.000010 27.23 0.56 9181 196 -196
DN10y(dn9bpre down) 1.03678 0.00218 0.08820 0.00349 0.09144 0.00363 0.006492 0.000022 15.32 0.61 10036 418 -416
DN-17-POST 1.05396 0.00139 0.09082 0.00108 0.09572 0.00114 0.054353 0.000145 1.84 0.02 y 10346 129 -129
DN-7-47 1.05794 0.00108 0.09181 0.00134 0.09713 0.00142 0.002746 0.000007 38.30 0.56 10464 160 -160
DN 7postB 1.04236 0.00107 0.09668 0.00067 0.10077 0.00070 0.008356 0.000013 12.58 0.09 n 11050 80 -80
DN6y(dn9B post) 1.04874 0.00102 0.09764 0.00287 0.10240 0.00301 0.011649 0.000085 9.16 0.28 y 11165 346 -345
DN9y(dn9b prebottom) 1.03918 0.00137 0.10535 0.00444 0.10947 0.00462 0.009156 0.000061 12.81 0.55 n 12097 542 -538
DN-51 pre IV 1.03187 0.00268 0.10615 0.00142 0.10953 0.00149 0.025043 0.000108 4.52 0.06 y 12197 173 -173
DN 7 post 1.04360 0.00107 0.10624 0.00123 0.11088 0.00129 0.008465 0.000033 13.56 0.16 n 12206 150 -150
DN-7-46 1.05616 0.00145 0.10627 0.00134 0.11224 0.00143 0.005237 0.000012 22.44 0.29 12208 163 -163
DN-17-PRE 1.03993 0.00378 0.10877 0.00534 0.11311 0.00557 0.018703 0.000088 6.74 0.33 y 12515 654 -650
DN-2-2 1.05553 0.00227 0.11931 0.00293 0.12593 0.00310 0.013666 0.000055 10.39 0.26 13802 362 -361
DN-4 pre (top) 1.05119 0.00122 0.14265 0.00169 0.14995 0.00178 0.014788 0.000039 10.54 0.13 y 16717 214 -214
DN8y(dn6C pre) 1.05426 0.00116 0.14291 0.00280 0.15067 0.00295 0.025554 0.000117 6.19 0.12 16749 355 -354
DN-66c-post (I) 1.05186 0.00282 0.14369 0.01171 0.15114 0.01233 0.024836 0.000587 9.52 0.81 y 16849 1495 -1475
DN 6B pre 1.05783 0.00150 0.15336 0.00237 0.16223 0.00252 0.011280 0.000046 14.95 0.24 18079 304 -304
DN 4 pre 1.06953 0.00113 0.16814 0.00134 0.17983 0.00145 0.001742 0.000004 106.97 0.87 n 19981 175 -175
DN-4 pre II (post) 1.03404 0.00129 0.16915 0.00276 0.17491 0.00286 0.027329 0.000098 6.65 0.11 y 20132 362 -361
DEN-2 pre 1.02887 0.00097 0.18043 0.00293 0.18564 0.00302 0.023520 0.000085 8.10 0.13 y 21619 390 -388
DN-6c pre I 1.10503 0.00150 0.18607 0.00207 0.20561 0.00231 0.022379 0.000049 9.42 0.11 y 22317 276 -276
DN-19-PRE-II 1.03311 0.00165 0.19322 0.00314 0.19962 0.00326 0.036963 0.000153 5.54 0.09 y 23323 425 -423
DN-47 pre II 1.04122 0.00072 0.19454 0.00183 0.20256 0.00191 0.020953 0.000070 9.83 0.10 y 23494 246 -246
DN-45 post 1.03315 0.00131 0.19801 0.00201 0.20457 0.00210 0.127528 0.000358 1.64 0.02 y 23969 273 -273
DN3y(dn4-pre) 1.07078 0.00122 0.20100 0.00267 0.21523 0.00287 0.007581 0.000029 29.63 0.41 n 24343 364 -362
DN 7 pre 1.06103 0.00116 0.20218 0.00145 0.21452 0.00156 0.011100 0.000036 19.77 0.15 y 24511 198 -198
DN-2-1 1.07159 0.00258 0.20490 0.00639 0.21957 0.00687 0.006287 0.000032 37.01 1.17 y 24871 875 -868
DN-48 post 1.07019 0.00201 0.21909 0.00146 0.23447 0.00162 0.002970 0.000008 81.34 0.56 n 26820 203 -203
DN-48 pre 1.06698 0.00153 0.23135 0.00210 0.24684 0.00226 0.005485 0.000023 46.27 0.45 n 28534 296 -296
DN-45 pre 1.01720 0.00139 0.23546 0.00807 0.23951 0.00821 0.030836 0.000254 7.89 0.28 y 29176 1154 -1142
DN-63-post 1.08810 0.00131 0.23978 0.00158 0.26090 0.00174 0.004805 0.000012 81.12 0.56 n 29701 225 -225
DN-37a-pre 1.07969 0.00213 0.24685 0.00145 0.26652 0.00165 0.001866 0.000004 145.54 0.84 n 30719 211 -211
DN-21pre-I 1.07807 0.00197 0.25861 0.00264 0.27880 0.00289 0.005144 0.000013 55.60 0.57 y 32420 387 -386
DN-7-45 1.09876 0.00149 0.26418 0.00166 0.29027 0.00187 0.011424 0.000024 25.95 0.17 33202 245 -245
DN 6C pre 1.07073 0.00096 0.27134 0.00237 0.29054 0.00255 0.001669 0.000003 177.99 1.57 34300 352 -352
DN-6c pre II 1.07306 0.00148 0.27851 0.00236 0.29886 0.00256 0.003601 0.000014 84.97 0.78 n 35363 354 -354
DN7y(dn6C pre) 1.07398 0.00147 0.28225 0.00319 0.30313 0.00345 0.002120 0.000004 146.36 1.67 35921 483 -481
DN-68b-pre 1.07626 0.00493 0.28627 0.00774 0.30810 0.00845 0.008858 0.000055 43.68 1.19 36522 1185 -1171
DN-47 post I 1.06773 0.00153 0.29022 0.00259 0.30987 0.00280 0.004028 0.000014 78.61 0.74 n 37136 398 -396
DN-44 post 1.07758 0.00301 0.29846 0.00285 0.32161 0.00320 0.000935 0.000005 354.47 3.62 n 38375 444 -442
DN-44 pre 1.06962 0.00277 0.29967 0.00458 0.32054 0.00497 0.006032 0.000025 55.00 0.86 38577 707 -708
DN-63-pre II 1.07924 0.00052 0.30333 0.00183 0.32737 0.00198 0.001445 0.000004 230.39 1.50 n 39122 283 -283
DN-36 pre III 1.08074 0.00157 0.32781 0.00176 0.35427 0.00197 0.018083 0.000047 19.92 0.11 y 42965 285 -285
DN-33C1-PRE 1.03957 0.00231 0.32881 0.01284 0.34182 0.01337 0.023024 0.000194 15.32 0.61 n 43241 2094 -2055
DN-52 post 1.07331 0.00247 0.33114 0.00399 0.35542 0.00436 0.006495 0.000021 55.90 0.68 n 43519 652 -647
DN-19-PRE-I 1.06999 0.00228 0.36921 0.00441 0.39505 0.00479 0.018431 0.000072 22.00 0.27 n 49829 762 -756
DN-47 pre I 1.05901 0.00146 0.37049 0.00319 0.39235 0.00342 0.020007 0.000057 20.07 0.18 y 50089 553 -550
DN-40-pre II 0.92599 0.00159 0.38749 0.03322 0.35881 0.03077 0.015372 0.001397 23.54 2.94 y 53717 6189 -5841
DN-21 pre II 1.04397 0.00132 0.39452 0.00253 0.41186 0.00270 0.020446 0.000056 20.47 0.14 y 54345 457 -456
DN 9B pre 1.05794 0.00184 0.40077 0.00267 0.42399 0.00291 0.007702 0.000019 56.30 0.39 n 55394 488 -486
DN-52 pre 1.07588 0.00156 0.40291 0.00267 0.43348 0.00294 0.005633 0.000015 78.36 0.55 n 55692 488 -485
DN-51 post I 1.05778 0.00176 0.42081 0.00312 0.44512 0.00339 0.020085 0.000041 22.59 0.17 n 59048 590 -587
DN-40 pre-II 1.04746 0.00271 0.42505 0.01276 0.44522 0.01342 0.016911 0.000021 27.06 0.81 n 59897 2429 -2376
DN 6A pre (post) 1.07952 0.00155 0.42623 0.00219 0.46013 0.00245 0.001532 0.000003 305.29 1.59 n 59936 416 -415
DN-66c-post II 1.18317 0.00280 0.43225 0.00576 0.51143 0.00692 0.009720 0.000039 65.53 0.90 60527 1080 -1069
DN-14A-PRE-I 1.00241 0.00069 0.44900 0.00260 0.45008 0.00262 0.072954 0.000224 6.26 0.04 y 64801 517 -516
DN-63-pre I 1.04106 0.00165 0.46048 0.00208 0.47938 0.00229 0.053326 0.000129 11.64 0.06 y 66781 427 -426
DN-14a-preI 1.00621 0.00065 0.49026 0.00413 0.49330 0.00417 0.075309 0.000242 6.68 0.06 73220 890 -882
DN-25 post II 1.02651 0.00151 0.52357 0.00317 0.53745 0.00335 0.032306 0.000085 16.91 0.11 y 80306 738 -733
DN-66c-pre I 1.08715 0.00161 0.57708 0.00308 0.62737 0.00348 0.046079 0.000109 9.58 0.05 y 92162 790 -785
DN-34a- post 1.04353 0.00278 0.64757 0.00394 0.67576 0.00449 0.048901 0.000125 17.75 0.10 112216 1264 -1247
DN-51 pre I 1.01478 0.00186 0.70284 0.00301 0.71323 0.00332 0.081740 0.000223 8.84 0.04 y 131346 1171 -1158
DN-33c2-post 1.05619 0.00251 0.71582 0.00474 0.75605 0.00532 0.018440 0.000043 41.70 0.27 134388 1848 -1814
DN-46 pre I 1.03657 0.00146 0.71835 0.00254 0.74462 0.00283 0.032753 0.000095 22.99 0.10 y 136133 1017 -1008
DN-25 post I 0.97948 0.00241 0.71237 0.03443 0.69775 0.03377 0.063813 0.002499 11.03 0.69 136503 14315 -12605
DN-66b-pre 1.00470 0.00290 0.72369 0.03047 0.72708 0.03068 0.123950 0.002547 9.08 0.42 y 139648 12826 -11444
DN-34a-pre II 1.06637 0.00318 0.74725 0.00514 0.79685 0.00598 0.004753 0.000016 108.57 0.76 n 146004 2253 -2203
DN-36 post-II 0.98185 0.00116 0.73641 0.00484 0.72304 0.00482 0.118289 0.000354 7.56 0.05 y 146262 1858 -2302
DN-33c2-pre 1.05609 0.00222 0.74735 0.00380 0.78927 0.00434 0.016461 0.000033 48.73 0.24 146544 1674 -1644
DN-46 pre II 1.05637 0.00186 0.75339 0.00598 0.79586 0.00647 0.008694 0.000023 92.76 0.75 y 149020 2619 -2556
DN-36 pre II 1.04813 0.00213 0.76509 0.00391 0.80192 0.00441 0.012018 0.000040 47.62 0.27 154473 1861 -1824
DN-34a-pre I 1.02974 0.00248 0.77247 0.00427 0.79544 0.00479 0.044464 0.000120 18.11 0.10 y 158935 2155 -2108
DN-22-POST-II 1.06510 0.00245 0.78766 0.00490 0.83893 0.00556 0.009551 0.000025 89.14 0.56 n 163707 2507 -2446
DN-46 post 0.95424 0.00121 0.79093 0.00483 0.75474 0.00471 0.108059 0.000344 7.07 0.05 y 174544 2862 -2784
DN-37a post 0.94086 0.00138 0.79625 0.00363 0.74915 0.00359 0.185180 0.000610 7.90 0.04 y 178984 2362 -1790
DN-27-II 0.99633 0.00134 0.85107 0.00344 0.84795 0.00361 0.049629 0.000082 17.32 0.07 207662 2776 -2702
DN-62 post II 1.04862 0.00208 0.86174 0.00726 0.90364 0.00782 0.036535 0.000148 25.14 0.23 y 207847 5571 -5291
DN-40-pre I 1.00703 0.00138 0.89247 0.00365 0.89875 0.00387 0.039360 0.000107 23.16 0.11 y 240828 4005 -3857
DN-26top-postI 1.01528 0.00082 0.90344 0.00335 0.91724 0.00348 0.074261 0.000126 12.53 0.05 250043 3850 -3717
DN-62 post I 1.04910 0.00090 0.91456 0.01086 0.95946 0.01142 0.071402 0.000550 13.56 0.19 y 253340 12464 -11197
DN-36 post I 1.03745 0.00347 0.91212 0.00558 0.94628 0.00660 0.029360 0.000076 25.69 0.14 253643 7157 -6679
DN-40 post I (2) 0.95030 0.00114 0.91932 0.00524 0.87363 0.00509 0.064856 0.000211 13.63 0.09 296208 9310 -9456
DN-65 post 1.05926 0.00101 0.95402 0.00566 1.01056 0.00607 0.004511 0.000019 226.13 1.63 n 301492 10009 -9185
DN-42e-pre 1.07104 0.00118 0.96297 0.00490 1.03138 0.00537 0.057652 0.000147 18.11 0.10 n 311281 9461 -8720
DN-66c-pre II 1.03939 0.00090 0.95915 0.00800 0.99693 0.00836 0.066596 0.000188 32.63 0.28 y 320296 17481 -15087
DN-36 pre I 1.02635 0.00142 0.95785 0.00293 0.98310 0.00330 0.064699 0.000149 32.60 0.11 y 325384 7240 -6771
DN34a-pre III 1.02381 0.00184 0.96007 0.00525 0.98293 0.00566 0.045409 0.000193 22.20 0.15 y 331793 13731 -12152
DN-65 pre 1.04065 0.00140 0.96909 0.00786 1.00848 0.00829 0.001810 0.000006 561.97 4.90 n 340805 21364 -17886
DN-22-POST-I 0.94199 0.00197 0.95166 0.00377 0.89646 0.00401 0.163262 0.000313 5.55 0.02 y 394924 24176 -19364
DN-22-PRE-II 1.02405 0.00208 0.98211 0.00450 1.00573 0.00504 0.075199 0.000194 13.53 0.07 y 395927 22847 -18817
DN-40-post I 0.91731 0.00264 0.97600 0.00388 0.89530 0.00440 0.071726 0.000213 12.62 0.04 y 873592 -11608 19656
DN-26top-preI 1.00029 0.00102 1.05743 0.00178 1.05773 0.00208 0.102962 0.000177 10.36 0.02 y eq. 150 -150
DN-62 pre I 1.01571 0.00056 1.01743 0.00406 1.03341 0.00416 0.083724 0.000260 12.45 0.06 y eq.
DN-22-PRE-I 0.98376 0.00180 0.99498 0.00336 0.97882 0.00376 0.093713 0.000251 10.56 0.04 y eq. 2658 -2590
53

The plots illustrated in Figures 17 and 18 may serve as indicators for sample clusters,
which could lend statistical reliability to speleo-seismite ages from Denya Cave, yet with
no precise dating the uncertainty of these results is very large. Using the results from
these plots, which indicate age clusters, an age cluster analysis was made (see below).
4.2 Age cluster analysis
Another way to calculate sample ages is by using equation [2] according to Broecker
(1963), based on isotopic ratios of 230 Th/ 238 U and 234 U/ 238 U. Those ages can be plotted on
a U-series evolution diagram with isochron lines and initial 234 U/ 238 U evolution curves
(Fig. 19).
Adding a third axis (z= 232 Th/ 238 U) to the evolution diagram, age calculations can be
presented using a regression for an isochron line in three dimensions. The x-y plane
intercepts of this 3-D isochron define the ratios used to calculate a 230 Th/U age and initial
234 U/ 238 U (Ludwig and Titterington, 1994). Age calculations were done using Isoplot3.7,
where one age was calculated for all samples which plotted reasonably well on a three
dimensional isochron plot. The isochron plots were calculated for all samples of similar
uncorrected ages (as indicated by Figs 17 and 18) and then modifications were made
according to the criteria elaborated above (see ch. 3.3.3- Cluster dating). These isochron
age calculations (elaborated in Figs. 20-28), are termed sample age clusters and
considered to be indicators of seismic events that affected Denya Cave.
54

1.14
1.10
1.06
234 U/
238 U
1.02
0.98
0.94
0.90
0.0 0.2 0.4 0.6 0.8 1.0
230 Th/ 238 U
Figure 19: U-series evolution diagram for Denya Cave seismite samples (red rectangles). Data are
based on isotopic ratios illustrated in Table 6.
55

Sample name 230/238 err 234/238 err 232/238 err 230/232 err Det. Age (y) + - Type
DN-51 pre III 0.04590 0.00121 1.04455 0.00108 0.004875 0.000019 10.15 0.27 y 4886 131 131 E
DN-2-3 0.04973 0.00230 1.04588 0.00237 0.002880 0.000022 22.50 1.05 n 5296 250 250 A
DN-2-4 0.05875 0.00206 1.04588 0.00152 0.004098 0.000024 16.88 0.60 y 6285 227 227 A
DN-66c-pre III 0.08397 0.00193 1.05658 0.00100 0.038891 0.000187 1.93 0.05 y 9000 1495 1475 E
DN-17-POST 0.09572 0.00114 1.05396 0.00139 0.054353 0.000145 1.84 0.02 y 10346 129 129 A
230
Th/U Age = 4.83 ±0.80 ka
1.08
data-point error ellipses are 2σ
Initial 234 U/ 238 U = 1.045 ±0.016
MSWD = 33, probability = 0.000
1.06
234 U/
238 U
1.04
1.02
0.03 0.05 0.07 0.09 0.11
230 Th/ 238 U
Figure 20: 5ka sample age cluster; 1. Sample isotopic ratio data table (red-pre samples, black-post
samples). 2. Isochron plot and age calculation (red crosses-uncorrected ages, green crossesprojected
data points). 3. Distribution of cluster samples in Denya Cave (red dots).
A cluster of ages at ca. 5ka is
shown in Figure 20. This age is
post
10.35ka
based on four pre- and post-seismic
A-1
event samples, from around the
E-1
cave, giving the age of the event a
pre III
9ka
viable constraint. Two of the
samples are of type A seismites and
two are of poor quality (type E)
DN-1
A-1
4-post
6.28ka
3-post
5.3ka
E-1
seismites (Fig. 21). The age
calculation yielded a minimal
Seismic contact
pre III
4.89ka
scatter isochron plot.
Figure 21: Age cluster ~5ka samples
56

Sample name 230/238 err 234/238 err 232/238 err 230/232 err Det. Age (y) + - Type
DN-7-46b-post 0.08454 0.00174 1.04368 0.00212 0.00345 0.00001 27.23 0.56 9181 196 196 A
DN-7-47 0.09713 0.00142 1.05794 0.00108 0.00275 0.00001 38.30 0.56 10464 160 160 A
DN 7postB 0.10077 0.00070 1.04236 0.00107 0.00836 0.00001 12.58 0.09 n 11050 80 80 A
DN-9B (post) 0.10240 0.00301 1.04874 0.00102 0.01165 0.00009 9.16 0.28 y 11165 346 345 C
DN-9b pre(bottom) 0.10947 0.00462 1.03918 0.00137 0.00916 0.00006 12.81 0.55 n 12097 542 538 C
DN-51 pre IV 0.10953 0.00149 1.03187 0.00268 0.02504 0.00011 4.52 0.06 y 12197 173 173 E
DN 7 post 0.11088 0.00129 1.04360 0.00107 0.00847 0.00003 13.56 0.16 n 12206 150 150 A
DN-7-46 0.11224 0.00143 1.05616 0.00145 0.00524 0.00001 22.44 0.29 12208 163 163 A
DN-17-PRE 0.11311 0.00557 1.03993 0.00378 0.01870 0.00009 6.74 0.33 y 12515 654 650 A
DN-2-2 0.12593 0.00310 1.05553 0.00227 0.01367 0.00005 10.39 0.26 13802 362 361 A
DN-45 post 0.20457 0.00210 1.03315 0.00131 0.12753 0.00036 1.64 0.02 y 23969 273 273 A
data-point error ellipses are 2σ
230 Th/U Age = 10.42 ±0.69 ka
1.07
Initial 234 U/ 238 U = 1.050 ±0.024
MSWD = 107, probability = 0.000
1.06
234 U/
238 U
1.05
1.04
1.03
1.02
0.04 0.08 0.12 0.16 0.20 0.24
230 Th/ 238 U
Figure 22: 10.4ka sample age cluster; 1. Sample isotopic ratio data table (red-pre samples, black-post
samples). 2. Isochron plot and age calculation (red crosses-uncorrected ages, green crosses- projected
data points). 3. Distribution of cluster samples in Denya Cave (red dots).
DN-1
46-post
12.21ka
46b-post
9.18ka
A cluster of ages at ca. 10.5ka is shown in Figure 22. This age is based on six seismite
A-1
2-pre
13.79ka
Seismic contact
Seismic contact
post
23.97ka
A-1
post
12.21ka
post B
11.05ka
pre
12.51ka
A-1
Seismic contact
(1)pre (post)
11.17ka
(2)pre (bottom)
12.1ka
C-1
samples of pre- and postseismic
event samples from
different areas of the cave.
Four of the samples are type
A seismite samples (Fig. 23).
This isochron calculated age
is considered to be very
accurate since it is derived
from five DN-7 post-seismite
samples, which is a type A
seismite (Fig. 23).
E-1
C-1
DN-45
pre IV
12.2ka
Figure 23: Age cluster ~10.5ka
samples.
57

Sample name 230/238 err 234/238 err 232/238 err 230/232 err Det. Age (y) + - Type
DN-4 pre (top) 0.14995 0.00178 1.05119 0.00122 0.014788 0.000039 10.54 0.13 y 16717 214 214 C
DN8y(dn6C pre) 0.15067 0.00295 1.05426 0.00116 0.025554 0.000117 6.19 0.12 16749 355 354 C
DN-66c-post (I) 0.15114 0.01233 1.05186 0.00282 0.024836 0.000587 9.52 0.81 y 16849 1495 1475 A
DN 6B pre 0.16223 0.00252 1.05783 0.00150 0.011280 0.000046 14.95 0.24 18079 304 304 C
DN 4 pre 0.17983 0.00145 1.06953 0.00113 0.001742 0.000004 106.97 0.87 n 19981 175 175 C
DN-4 pre II (post) 0.17491 0.00286 1.03404 0.00129 0.027329 0.000098 6.65 0.11 y 20132 362 361 C
DEN-2 pre 0.18564 0.00302 1.02887 0.00097 0.023520 0.000085 8.10 0.13 y 21619 390 388 C
DN-6c pre I 0.20561 0.00231 1.10503 0.00150 0.022379 0.000049 9.42 0.11 y 22317 276 276 C
DN-19-PRE-II 0.19962 0.00326 1.03311 0.00165 0.036963 0.000153 5.54 0.09 y 23323 425 423 C
DN-47 pre II 0.20256 0.00191 1.04122 0.00072 0.020953 0.000070 9.83 0.10 y 23494 246 246 A
DN-45 post 0.20457 0.00210 1.03315 0.00131 0.127528 0.000358 1.64 0.02 y 23969 273 273 A
DN3y(dn4-pre) 0.21523 0.00287 1.07078 0.00122 0.007581 0.000029 29.63 0.41 n 24343 364 362 C
DN 7 pre 0.21452 0.00156 1.06103 0.00116 0.011100 0.000036 19.77 0.15 y 24511 198 198 C
data-point error ellipses are 2σ
230 Th/U Age = 20.8 ±3.0 ka
1.12
Initial 234 U/ 238 U = 1.060 ±0.063
MSWD = 712, probability = 0.000
1.10
234 U/
238 U
1.08
1.06
1.04
1.02
0.12 0.14 0.16 0.18 0.20 0.22 0.24
230 Th/ 238 U
Figure 24: 21ka sample age cluster; 1. Sample isotopic ratio data table (red-pre samples, black-post
samples). 2. Isochron plot and age calculation (red crosses-uncorrected ages, green crossesprojected
data points). 3. Distribution of cluster samples in Denya Cave (red dots).
A cluster of ages at ca. 21ka is shown in Figure 24. This age is based on eight
seismite samples, mostly of pre-seismic event samples, from all parts of the upper
chamber of the cave. Most of the samples are type C seismites (Fig. 25). The isochron
C-1
A-1
pre
24.51ka
DEN-2
pre
21.62ka
pre
18.07ka
b DN-6c
C-3
pre
16.75ka
pre I
22.32ka
(4) pretop
16.72ka
(2) pre II
19.98ka
A-2
C-1
(1) pre I
24.34ka
post I
16.85ka
(3) pre
III (pos t )
20.14ka
pre II
23.49ka
E-1
A-1
DN-47
pre II
23.32ka
post
23.97ka
C-1
plot is very scattered and yet it
was established as a viable
isochron because four DN-4 preseismite
samples come from the
same lamina, despite the fact that
they show different ages, and the
same is true of two DN-6c preseismite
samples (Fig. 25).
Sample DN-7 pre is considered
to be a reliable seismite sample.
Figure 25: Age cluster ~21ka samples.
58

Sample name 230/238 err 234/238 err 232/238 err 230/232 err Det. Age (y) + - Type
DN-48 post 0.23447 0.00162 1.07019 0.00201 0.002970 0.000008 81.34 0.56 n 26820 203 203 A
DN-48 pre 0.24684 0.00226 1.06698 0.00153 0.005485 0.000023 46.27 0.45 n 28534 296 296 A
DN-45 pre 0.23951 0.00821 1.01720 0.00139 0.030836 0.000254 7.89 0.28 y 29176 1154 1142 A
DN-63-post 0.26090 0.00174 1.08810 0.00131 0.004805 0.000012 81.12 0.56 n 29701 225 225 A
DN-37a-pre 0.26652 0.00165 1.07969 0.00213 0.001866 0.000004 145.54 0.84 n 30719 211 211 D
DN-21pre-I 0.27880 0.00289 1.07807 0.00197 0.005144 0.000013 55.60 0.57 y 32420 387 386 C
230
Th/U Age = 29.1 ±3.3 ka
1.12
data-point error ellipses are 2σ
Initial 234 U/ 238 U = 1.095 ±0.044
MSWD = 220, probability = 0.000
1.10
1.08
234 U/
238 U
1.06
1.04
1.02
1.00
0.22 0.24 0.26 0.28 0.30
230 Th/ 238 U
Figure 26: 29ka sample age cluster; 1. Sample isotopic ratio data table (red-pre samples, black-post
samples). 2. Isochron plot and age calculation (red crosses-uncorrected ages, green crossesprojected
data points). 3. Distribution of cluster samples in Denya Cave (red dots).
A cluster of age at ca. 29ka is shown in Figure 26. This age is based on five different
seismite samples, three of which are type A (Fig. 27). The age is a well constrained
because it is based on pre- and post seismite samples DN-48 (type B) (Fig. 27). Any other
evidence can be seen
pre
30.72ka
DN-45
as corroborative.
A-1
D-1
pre
29.18ka
DN-37
pre I
32.42ka
DN-63
post
29.7ka
post
26.83ka
C-1
A-5
pre
28.53ka
B-1
Figure 27: Age cluster
~ 29ka samples.
59

Sample name 230/238 err 234/238 err 232/238 err 230/232 err Det. Age (y) + - Type
DN-68b-pre 0.30810 0.00845 1.07626 0.00493 0.008858 0.000055 43.68 1.19 36522 1185 1171 C
DN-47 post I 0.30987 0.00280 1.06773 0.00153 0.004028 0.000014 78.61 0.74 n 37136 398 396 A
DN-44 post 0.32161 0.00320 1.07758 0.00301 0.000935 0.000005 354.47 3.62 n 38375 444 442 A
DN-44 pre 0.32054 0.00497 1.06962 0.00277 0.006032 0.000025 55.00 0.86 38577 707 708 A
DN-63-pre II 0.32737 0.00198 1.07924 0.00052 0.001445 0.000004 230.39 1.50 n 39122 283 283 A
DN-36 pre III 0.35427 0.00197 1.08074 0.00157 0.018083 0.000047 19.92 0.11 y 42965 285 285 E
DN-33C1-PRE 0.34182 0.01337 1.03957 0.00231 0.023024 0.000194 15.32 0.61 n 43241 2094 2055 A
DN-52 post 0.35542 0.00436 1.07331 0.00247 0.006495 0.000021 55.90 0.68 n 43519 652 647 A
230
Th/U Age = 38.0 ±2.7 ka
1.12
data-point error ellipses are 2σ
Initial 234 U/ 238 U = 1.089 ±0.028
MSWD = 105, probability = 0.000
1.10
234 U/
238 U
1.08
1.06
1.04
1.02
0.27 0.29 0.31 0.33 0.35 0.37
230 Th/ 238 U
Figure 28: 38ka sample age cluster; 1. Sample isotopic ratio data table (red-pre samples, black-post
samples). 2. Isochron plot and age calculation (red crosses-uncorrected ages, green crossesprojected
data points). 3. Distribution of cluster samples in Denya Cave (red dots).
post
38.37ka
A cluster of ages at ca. 38ka is shown in Figure 28. This age is based on six pre- and
DN-63
pre II
39.12ka
pre
38.58ka
post I
37.14ka
pre
43.24ka
A-4
A-5
A-2
DN-33c-1
pre
36.52ka
post
43.52ka
C-1
DN-52
post-seismite samples from around
the upper chamber of the cave, four
of which are type A seismite samples
(Fig. 29). The age calculation of the
isochron is approximately the same
as the uncorrected ages of samples
DN-44 pre and post, which constrain
the age of the seismic event very
accurately, even though the isochron
seems highly scattered. The two other
samples in this cluster can be viewed
as corroborative evidence.
A-4
DN-44
A-3
Figure 29: Age cluster ~38ka samples.
60

Sample name 230/238 err 234/238 err 232/238 err 230/232 err Det. Age (y) + - Type
DN-52 pre 0.43348 0.00294 1.07588 0.00156 0.005633 0.000015 78.36 0.55 n 55692 488 485 A
DN-51 post I(pre) 0.44512 0.00339 1.05778 0.00176 0.020085 0.000041 22.59 0.17 n 59048 590 587 E
DN 6A pre 0.46013 0.00245 1.07952 0.00155 0.001532 0.000003 305.29 1.59 n 59936 416 415 C
DN-14A-PRE-I 0.45008 0.00262 1.00241 0.00069 0.072954 0.000224 6.26 0.04 y 64801 517 516 C
DN-63-pre I 0.47938 0.00229 1.04106 0.00165 0.053326 0.000129 11.64 0.06 y 66781 427 426 A
DN-14a-preI 0.49330 0.00417 1.00621 0.00065 0.075309 0.000242 6.68 0.06 73220 890 882 C
230
Th/U Age = 57.9 ±5.2 ka
data-point error ellipses are 2σ
Initial 234 U/ 238 U = 1.097 ±0.040
MSWD = 156, probability = 0.000
1.11
1.09
1.07
234 U/
238 U
1.05
1.03
1.01
0.99
0.41 0.43 0.45 0.47 0.49 0.51
230 Th/ 238 U
Figure 30: 58ka sample age cluster; 1. Sample isotopic ratio data table (red-pre samples, black-post
samples). 2. Isochron plot and age calculation (red crosses-uncorrected ages, green crossesprojected
data points). 3. Distribution of cluster samples in Denya Cave (red dots).
A cluster of ages at ca. 58ka is shown in Figure 30. This age is based strictly on preseismic
event samples from different parts of the cave, two of which are type A seismites
pre
59.94ka
A-5
DN-63
C-3
post I
(maybe pre)
59.05ka
pre I
66.78ka
DN-51
E-1
C-1
DN-14
DN-52
Seismic contact
pre
55.69ka
pre
73.2ka
A-3
pre
64.8ka
(Fig. 31). The isochron plot
is scattered and gives a
relatively high error on the
calculated age. Nevertheless,
two DN-14a samples from
the same lamina were
calculated. This age indicates
that some time after ca. 58ka
a seismic event occurred,
which affected the whole
cave.
Figure 31: Age cluster ~58ka
samples.
61

Sample name 230/238 err 234/238 err 232/238 err 230/232 err Det. Age (y) + - Type
DN-51 pre I 0.71323 0.00332 1.01478 0.00186 0.081740 0.000223 8.84 0.04 y 131346 1171 1158 A
DN-33c2-post 0.75605 0.00532 1.05619 0.00251 0.018440 0.000043 41.70 0.27 134388 1848 1814 A
DN-46 pre I 0.74462 0.00283 1.03657 0.00146 0.032753 0.000095 22.99 0.10 y 136133 1017 1008 A
DN-25 post I 0.69775 0.03377 0.97948 0.00241 0.063813 0.002499 11.03 0.69 136503 14315 12605 D
DN-66b-pre 0.72708 0.03068 1.00470 0.00290 0.123950 0.002547 9.08 0.42 y 139648 12826 11444 E
230
Th/U Age = 137 ±29 ka
data-point error ellipses are 2σ
Initial 234 U/ 238 U = 1.085 ±0.067
MSWD = 179, probability = 0.000
1.12
1.08
234 U/
238 U
1.04
1.00
0.96
0.64 0.68 0.72 0.76 0.80 0.84
230
Th/ 238 U
Figure 32: 137ka sample age cluster; 1. Sample isotopic ratio data table (red-pre samples, black-post
samples). 2. Isochron plot and age calculation (red crosses-uncorrected ages, green crosses- projected
data points). 3. Distribution of cluster samples in Denya Cave (red dots).
A cluster of ages at ca. 137ka is shown in Figure 32. This age is based on five pre-
and post-seismite samples from around the upper chamber of the cave, three of which are
type A speleo-seismites (Fig. 33). The large error of the calculated age could be attributed
A-3
to the large error of some of
D-2
the individual samples (due
to a low accuracy of
dating). Nevertheless, the
post I
136.5ka
DN-46
pre I
136.13ka
A-2
isochron calculation yielded
a very large error, therefore
it is noted as an event
Seismic contact
post
134.38ka
pre
139.65ka
which was recorded at the
time interval between ca.
110 and 170ka.
A-2
DN-33c2
E-1
pre I
(maybe post)
131.35ka
DN-51
Figure 33: Age cluster ~137ka
samples.
62

Sample name 230/238 err 234/238 err 232/238 err 230/232 err Det. Age (y) + - Type
DN-34a-pre II 0.7968 0.0060 1.0664 0.0032 0.004753 0.000016 108.57 0.76 n 146004 2253 2203 A
DN-36 post-II 0.7230 0.0048 0.9818 0.0012 0.118289 0.000354 7.56 0.05 y 146262 1858 2302 A
DN-33c2-pre 0.7893 0.0043 1.0561 0.0022 0.016461 0.000033 48.73 0.24 146544 1674 1644 A
DN-46 pre II 0.7959 0.0065 1.0564 0.0019 0.008694 0.000023 92.76 0.75 y 149020 2619 2556 A
230
Th/U Age = 147.6 ±5.4 ka
1.10
data-point error ellipses are 2σ
Initial 234 U/ 238 U = 1.100 ±0.012
MSWD = 5.4, probability = 0.000
1.08
1.06
234 U/
238 U
1.04
1.02
1.00
0.98
0.96
0.70 0.72 0.74 0.76 0.78 0.80 0.82
230 Th/ 238 U
Figure 34: 148ka sample age cluster; 1. Sample isotopic ratio data table (red-pre samples, black-post
samples). 2. Isochron plot and age calculation (red crosses-uncorrected ages, green crossesprojected
data points). 3. Distribution of cluster samples in Denya Cave (red dots).
A cluster of ages at ca. 148ka is shown in Figure 34. This age is based on a relatively
accurate isochron plot, derived from four different type A speleo-seismites (Fig. 35).
DN-46
A-3
DN-36
A-5
Samples DN-36, DN-34
and DN-46 are flowstone
cores from the same area of
the cave. It is therefore
pre II
149.02ka
post II
146.26ka
Seismic contact
likely that they recorded
the same event, which is
DN-33c2
DN-34a
A-5
well constrained since they
Seismic contact
Seismic contact
are both pre- and postseismite
samples.
A-2
pre
146.54ka
pre II
146ka
Figure 35: Age cluster
~147ka samples.
63

Sample name 230/238 err 234/238 err 232/238 err 230/232 err Det. Age (y) + - type
DN-36 pre II 0.80192 0.00441 1.04813 0.00213 0.012018 0.000040 47.62 0.27 154473 1861 1824 A
DN-34a-pre I 0.79544 0.00479 1.02974 0.00248 0.044464 0.000120 18.11 0.10 y 158935 2155 2108 A
DN-22-POST-II 0.83893 0.00556 1.06510 0.00245 0.009551 0.000025 89.14 0.56 n 163707 2507 2446 A
DN-46 post 0.75474 0.00471 0.95424 0.00121 0.108059 0.000344 7.07 0.05 y 174544 2862 2784 A
DN-37a post 0.74915 0.00359 0.94086 0.00138 0.185180 0.000610 7.90 0.04 y 178984 2362 1790 D
230 Th/U Age = 160 ±45 ka
data-point error ellipses are 2σ
Initial 234 U/ 238 U = 1.079 ±0.095
MSWD = 408, probability = 0.000
1.10
1.06
234 U/
238 U
1.02
0.98
0.94
0.90
0.72 0.76 0.80 0.84 0.88
230 Th/ 238 U
Figure 36: 160ka sample age cluster; 1. Sample isotopic ratio data table (red-pre samples, black-post
samples). 2. Isochron plot and age calculation (red crosses-uncorrected ages, green crossesprojected
data points). 3. Distribution of cluster samples in Denya Cave (red dots).
A cluster of ages at ca. 160ka is shown in Figure 36. This age is based on five
flowstone samples, four of which are type A speleo-seismites (Fig. 37). The calculated
age has a large error, yet these samples originate from the same area of the cave, which
A-4
Seismic contact
pre I
158.94ka
DN-34a
A-5
DN-37a
post
178.98ka
Seismic contact
D-2
may indicate that they
recorded the same
event, which is well
constrained since they
are both pre- and postseismite
samples.
post II
163.7ka
A-5 DN-36
A-3
post
174.54ka
Seismic contact
Seismic contact
pre II
154.47ka
Seismic contact
DN-46
Figure 37: Age cluster
~160ka samples.4.2.1
Seismic events in
64

Seismic events in Denya Cave
Broken speleothems from Denya Cave yielded break ages that seemed to cluster at
specific times (e.g. ~10-12ka, ~20-24ka, ~29-32ka, ~37-40ka etc. see Table 4 and Figs,
17,18). This indicates that the ages are not random and that certain events affected the
whole cave simultaneously. When considering seismite types, each age cluster is also
classified according to its credibility as a precise indicator of a seismic event.
Single sample dating was not possible for Denya Cave seismites and therefore criteria
for creating sample age clusters through three-dimensional isochron plots were
established, yielding a corrected age for all seismite samples of the same age. This in turn,
established statistical means to discern ages of seismic events, which caused damage in
Denya Cave. Criteria for viable isochrons are based on morphological, special and
chemical factors. Seismic events discerned from Denya Cave seismites, using all
aforementioned criteria and three dimensional isochron plots are: 5.03±0.87ka,
10.42±0.69ka, 20.8±3.0ka, 29.1±3.3, 38.0±2.7ka, 57.9±5.2ka, 137±29ka, 147.6±5.4ka
and 160±45ka (Figs. 38, 39).
4.2.2 Isochron age cluster dating
As mentioned above, all seismite samples that plotted on isochron lines were used for
age calculations. In this study the criteria for establishing a reasonable isochron (see ch.
3.3-Age cluster dating) encompass not only geochemical criteria, but also take into
account structural features within the cave and stratigraphic considerations in the
speleothem sample laminae.
Table 7 shows that calculations using isochrons give average ages, causing some
samples to appear older, whereas a single correction would always cause them to be
younger (e.g. correction factor 1.8 ; Table 7). Essentially this means that the ages of
sample clusters are only significant when the samples are considered as a group. Since the
sampling technique is not as accurate as the actual results from the MC-ICP-MS, it seems
reasonable that any age of a seismic event obtained from this kind of research would
result from averaging individual sample ages.
When using three dimensional isochron calculations all samples are considered, even
those otherwise discarded because of their high detrital content. Those samples add to the
number of samples included in the average and yield more accurate ages because they
better constrain the isochron line.
65

By using the isochron technique some seismite samples of high quality (e.g. DN-42e;
see Appendix I-II) did not plot along an isochron line and were therefore discarded. Yet
those samples have a very long depositional hiatus (Fig. 15) and wouldn’t have been
strong indicators of earthquakes by themselves. Therefore, the isochron method also
permits to sort data, using only statistically viable samples.
While the precise age of each isochron, or set of seismite samples, might be disputed,
it is clear that they do seem to plot and give a reasonable age, which is stratigraphicaly
plausible. Furthermore, no clear isochrons were obtained for non-seismite samples, and
when the DEM was factored in, the degree of isochron accuracy rose. The scattering of a
large number of the results could be explained by an inherent inaccuracy in the sampling
technique. It is therefore clear that the ages obtained are not random, and while they may
vary within their margin of error, they are considered to be indicators of strong
earthquakes that affected Denya Cave. This study suggests that three dimensional
isochron plots solved the problem of the single age correction value, or lack thereof, for
Denya Cave speleothems. Use of this method has also created a reasonable way to derive
sample age clusters, which might indicate seismic events.
4.2.3 Considerations concerning MSWD
MSWD (Mean Square of Weighted Deviates) is the degree to which the observed
amount of scatter of the U-series data points from the isochron lines (the best-fit line) can
be explained by assigned analytical errors (Ludwig and Titterington, 1994).
Consequently, a high MSWD either means underestimated analytical errors or the
presence of non-analytical scatter (Ludwig, 2003). Brooks et al. (1972) suggested that a
satisfactory isochron must have an MSWD value that is lower than 2.5. Yet Davidson et
al. (2005) noted that for a given data set the MSWD deteriorates as the errors on the data
point decrease (a correlation line is harder to pass within the error bars). Since assigned
errors are quite small when using the MC-ICP-MS, it is highly likely that the MSWD
value is magnified, which in turn translates into degradation in the precision of the
isochron.
In this study, results have shown that the MSWD has very little effect on the precision
of ages obtained through Isoplot. Indeed, there seems to be no correlation at all between
the amount of scatter of the data points and their MSWD values. Moreover, when
comparing the four point isochron of 147.6ka (MSWD = 5.4) to that of the eleven point
66

isochron of 10.4ka (MSWD = 107), it seems that this value does not altogether portray
the statistical factors creating the isochron. When creating an isochron line for samples
from the same lamina (i.e. isochron samples; Figs. 15, 16 and Tables 1-3), it was expected
that they would plot comfortably along the lines and have a low MSWD. However, those
samples have varying MSWD values, all of them much higher than 2.5. This observation
concurs with Davidson et al. (2005), who state that an isochron may not be acceptable on
the basis of statistical tests but can still be geologically meaningful, and vice versa. It is
for that reason that it is valid to expand all assigned errors by √MSWD, and the calculated
slope or intercept errors by a student's multiplier, as suggested by Ludwig and
Titterington (1994) and executed through Isoplot3.7. Using these methods and
considering these ideas, it seems likely that the isochrons in this study are reasonably
accurate.
67

1.14
1.10
1.06
234 U/
238 U
1.02
0.98
0.94
0.90
0.0 0.2 0.4 0.6 0.8 1.0
230 Th/ 238 U
Figure 38: U-series evolution diagram for Denya Cave seismite samples showing the projected
data, which yielded the isochron ages, and illustrating with circles the calculated ages. Circles
representing isochron calculations: Red-5ka, light blue-10.4ka, pink-21ka, green-29ka, brown-
38ka, purple-58ka, yellow-137ka, light green-147ka and dark blue-160ka.
68

data-point error ellipses are 2σ
1.14
1.10
234 U/
238 U
1.06
1.02
0.98
a
0.94
0.0 0.1 0.2 0.3 0.4 0.5 0.6
230 Th/ 238 U
data-point error ellipses are 2σ
1.08
1.04
234 U/
238 U
1.00
0.96
b
0.92
0.6 0.7 0.8 0.9 1.0 1.1
230 Th/ 238 U
Figure 39: U-series evolution diagrams for Denya Cave seismite samples showing
uncorrected ages and illustrating with circles the calculated ages yielded by their
isochrones. a) Samples of ages up to 100ka; red- 5ka isochron, and blue, pink, green,
brown represent 10.42ka, 21ka, 29ka, 38ka, and 58ka isochrons respectively. b)
Samples of ages between 100 and 200ka. Red, green and blue marks represent 137ka,
148ka and 160ka isochrones respectively.
69

Table 7: Comparison between the ages obtained by different dating techniques for
Denya Cave seismite samples (represented in ka). The samples are sorted by age.
Samples marked in light blue are samples that had no detrital material yet had a low
230 Th/ 232 Th ac<strong>tivity</strong> ratio. DN-2 samples 3 and 4 come from very close laminae in the
sample and show that the detrital content does in fact affect the age when a sample
contains detritus, even though they both have a low 230 Th/ 232 Th ac<strong>tivity</strong> ratio.
Dated sample name 230/238 err 234/238 err 232/238 err 230/232 err Det. Age-un.corr ± AgeCorr. (1.8) Clus. Age ±
DN-51 pre III 0.0459 0.00121 1.0445 0.00108 0.0049 0.00002 10.15 0.27 y 4.9 0.26 4.0 5 0.87
DN-2-3 0.0497 0.00230 1.0459 0.00237 0.0029 0.00002 22.50 1.05 n 5.3 0.50 4.8 5 0.87
DN-2-4 0.0588 0.00206 1.0459 0.00152 0.0041 0.00002 16.88 0.60 y 6.3 0.45 5.5 5 0.87
DN-51 pre II 0.0734 0.00261 0.9987 0.01697 0.0116 0.00009 6.63 0.18 y 8.3 0.54 6.1 5 0.87
DN-66c-pre III 0.0840 0.00193 1.0566 0.00100 0.0389 0.00019 1.93 0.05 y 9.0 2.97 0.5 5 0.87
DN-7-46b-post 0.0845 0.00174 1.0437 0.00212 0.0034 0.00001 27.23 0.56 9.2 0.39 8.6 10.4 0.69
DN-17-POST 0.0957 0.00114 1.0540 0.00139 0.0544 0.00014 1.84 0.02 y 10.3 0.26 0.2 5 0.87
DN-7-47 0.0971 0.00142 1.0579 0.00108 0.0027 0.00001 38.30 0.56 10.5 0.32 10.0 10.4 0.69
DN 7postB 0.1008 0.00070 1.0424 0.00107 0.0084 0.00001 12.58 0.09 n 11.1 0.16 9.5 10.4 0.69
DN6y(dn9B post) 0.1024 0.00301 1.0487 0.00102 0.0116 0.00009 9.16 0.28 y 11.2 0.69 9.1 10.4 0.69
DN9y(dn9b prebottom) 0.1095 0.00462 1.0392 0.00137 0.0092 0.00006 12.81 0.55 n 12.1 1.08 10.4 10.4 0.69
DN-51 pre IV 0.1095 0.00149 1.0319 0.00268 0.0250 0.00011 4.52 0.06 y 12.2 0.35 7.5 10.4 0.69
DN 7 post 0.1109 0.00129 1.0436 0.00107 0.0085 0.00003 13.56 0.16 n 12.2 0.30 10.7 10.4 0.69
DN-7-46 0.1122 0.00143 1.0562 0.00145 0.0052 0.00001 22.44 0.29 12.2 0.33 11.3 10.4 0.69
DN-17-PRE 0.1131 0.00557 1.0399 0.00378 0.0187 0.00009 6.74 0.33 y 12.5 1.30 9.1 10.4 0.69
DN-2-2 0.1259 0.00310 1.0555 0.00227 0.0137 0.00005 10.39 0.26 13.8 0.72 11.3 10.4 0.69
DN8y(dn6C pre) 0.1507 0.00295 1.0543 0.00116 0.0256 0.00012 6.19 0.12 16.7 0.71 12.1 20.8 3
DN 6B pre 0.1622 0.00252 1.0578 0.00150 0.0113 0.00005 14.95 0.24 18.1 0.61 16.1 20.8 3
DN 4 pre 0.1798 0.00145 1.0695 0.00113 0.0017 0.00000 106.97 0.87 n 20.0 0.35 19.7 20.8 3
DEN-2 pre 0.1856 0.00302 1.0289 0.00097 0.0235 0.00008 8.10 0.13 y 21.6 0.78 17.2 20.8 3
DN-19-PRE-II 0.1996 0.00326 1.0331 0.00165 0.0370 0.00015 5.54 0.09 y 23.3 0.85 16.4 20.8 3
DN-45 post 0.2046 0.00210 1.0331 0.00131 0.1275 0.00036 1.64 0.02 y 24.0 0.55 20.8 or 10.4 0.69
DN3y(dn4-pre) 0.2152 0.00287 1.0708 0.00122 0.0076 0.00003 29.63 0.41 n 24.3 0.73 23.0 20.8 3
DN 7 pre 0.2145 0.00156 1.0610 0.00116 0.0111 0.00004 19.77 0.15 y 24.5 0.40 22.5 20.8 3
DN-48 post 0.2345 0.00162 1.0702 0.00201 0.0030 0.00001 81.34 0.56 n 26.8 0.41 26.3 29 3.3
DN-48 pre 0.2468 0.00226 1.0670 0.00153 0.0055 0.00002 46.27 0.45 n 28.5 0.59 27.6 29 3.3
DN-45 pre 0.2395 0.00821 1.0172 0.00139 0.0308 0.00025 7.89 0.28 y 29.2 2.30 23.3 29 3.3
DN-63-post 0.2609 0.00174 1.0881 0.00131 0.0048 0.00001 81.12 0.56 n 29.7 0.45 29.1 29 3.3
DN-37a-pre 0.2665 0.00165 1.0797 0.00213 0.0019 0.00000 145.54 0.84 n 30.7 0.42 30.4 29 3.3
DN-21pre-I 0.2788 0.00289 1.0781 0.00197 0.0051 0.00001 55.60 0.57 y 32.4 0.77 31.5 29 3.3
DN-68b-pre 0.3081 0.00845 1.0763 0.00493 0.0089 0.00005 43.68 1.19 36.5 2.36 35.2 38 2.7
DN-47 post I 0.3099 0.00280 1.0677 0.00153 0.0040 0.00001 78.61 0.74 n 37.1 0.79 36.4 38 2.7
DN-44 post 0.3216 0.00320 1.0776 0.00301 0.0009 0.00000 354.47 3.62 n 38.4 0.89 38.2 38 2.7
DN-44 pre 0.3205 0.00497 1.0696 0.00277 0.0060 0.00002 55.00 0.86 38.6 1.42 37.5 38 2.7
DN-63-pre II 0.3274 0.00198 1.0792 0.00052 0.0014 0.00000 230.39 1.50 n 39.1 0.57 38.9 38 2.7
DN-36 pre III 0.3543 0.00197 1.0807 0.00157 0.0181 0.00005 19.92 0.11 y 43.0 0.57 39.8 38 2.7
DN-33C1-PRE 0.3418 0.01337 1.0396 0.00231 0.0230 0.00019 15.32 0.61 n 43.2 4.15 39.0 38 2.7
DN-52 post 0.3554 0.00436 1.0733 0.00247 0.0065 0.00002 55.90 0.68 n 43.5 1.30 42.4 38 2.7
DN-52 pre 0.4335 0.00294 1.0759 0.00156 0.0056 0.00002 78.36 0.55 n 55.7 0.97 54.7 58 5.2
DN-51 post I 0.4451 0.00339 1.0578 0.00176 0.0201 0.00004 22.59 0.17 n 59.0 1.18 55.5 58 5.2
DN 6A pre (post) 0.4601 0.00245 1.0795 0.00155 0.0015 0.00000 305.29 1.59 n 59.9 0.83 59.7 58 5.2
DN-14A-PRE-I 0.4501 0.00262 1.0024 0.00069 0.0730 0.00022 6.26 0.04 y 64.8 1.03 50.2 58 5.2
DN-63-pre I 0.4794 0.00229 1.0411 0.00165 0.0533 0.00013 11.64 0.06 y 66.8 0.85 59.0 58 5.2
DN-14a-preI 0.4933 0.00417 1.0062 0.00065 0.0753 0.00024 6.68 0.06 73.2 1.77 58.2 58 5.2
DN-33c2-post 0.7560 0.00532 1.0562 0.00251 0.0184 0.00004 41.70 0.27 134.4 3.66 131.1 137 29
DN-46 pre I 0.7446 0.00283 1.0366 0.00146 0.0328 0.00010 22.99 0.10 y 136.1 2.02 130.1 137 29
DN-25 post I 0.6978 0.03377 0.9795 0.00241 0.0638 0.00250 11.03 0.69 136.5 26.92 123.4 137 29
DN-66b-pre 0.7271 0.03068 1.0047 0.00290 0.1239 0.00255 9.08 0.42 y 139.6 24.27 123.6 137 29
DN-34a-pre II 0.7968 0.00598 1.0664 0.00318 0.0048 0.00002 108.57 0.76 n 146.0 4.46 144.7 147.6 5.4
DN-36 post-II 0.7230 0.00482 0.9818 0.00116 0.1183 0.00035 7.56 0.05 y 146.3 4.16 125.5 147.6 5.4
DN-33c2-pre 0.7893 0.00434 1.0561 0.00222 0.0165 0.00003 48.73 0.24 146.5 3.32 143.7 147.6 5.4
DN-46 pre II 0.7959 0.00647 1.0564 0.00186 0.0087 0.00002 92.76 0.75 y 149.0 5.17 147.5 147.6 5.4
DN-36 pre II 0.8019 0.00441 1.0481 0.00213 0.0120 0.00004 47.62 0.27 154.5 3.69 151.4 160 45
DN-34a-pre I 0.7954 0.00479 1.0297 0.00248 0.0445 0.00012 18.11 0.10 y 158.9 4.26 150.6 160 45
DN-22-POST-II 0.8389 0.00556 1.0651 0.00245 0.0096 0.00003 89.14 0.56 n 163.7 4.95 162.1 160 45
DN-46 post 0.7547 0.00471 0.9542 0.00121 0.1081 0.00034 7.07 0.05 y 174.5 5.65 150.1 160 45
DN-37a post 0.7492 0.00359 0.9409 0.00138 0.1852 0.00061 7.90 0.04 y 179.0 4.15 157.1 160 45
70

5. Discussion
The purpose of the present study is to date large paleoseismic events along the CF
during the Quaternary using the ages of broken speleothems from Denya Cave.
Speleothems are dated using the uranium disequilibrium decay series. The use of the three
dimensional isochron was found to be the best method to determine the ages of speleoseismites.
The method reasonably generates age clusters, which are probably indicative of
seismic events that caused damage to Denya Cave speleothems. These age clusters are
based on statistically viable isochrons as well as structural and morphological criteria. A
comparison showed that some sample age clusters were similar to the ages determined in
other paleo-seismological studies in Israel (Table 4 and Fig. 29). The comparison
indicates that the breaks, which were identified in Denya Cave speleothems, are not
random and lends supportive evidence to the assumption that they represent seismic
events.
5.1 Seismic events recorded in Denya Cave speleothems
Analysis of U-Th ages of speleo-seismites in Denya Cave, using three dimensional
isochrons, yielded age clusters that are considered to represent nine seismic events during
the last 200kyr BP:
1. A seismic event at ~4.8(±0.8)ka is based on five pre and post seismite samples
from around the cave, among them DN-2, which is a type A speleo-seismite.
2. A seismic event at ~10.4(±0.69)ka is based on six pre and post seismite
samples from around the cave, where two are type A speleo-seismites (DN-7
and DN-17). This calculated age is considered accurate since it is based on 11
dated samples, of which four DN-7 post-seismite samples are considered to be
of the same age and two DN-9 pre-seismite samples that are likewise
considered to be of the same age.
3. A seismic event at ~20.8(±3.0)ka is based on eight seismite samples from
around the cave. Most of those are pre-seismite samples of type C speleoseismites.
This calculated age is based on 13 dated samples, of which four
DN-4 pre-seismite samples are considered to be of the same age and likewise
for two DN-6 pre-seismite samples. It is supported by DN-7 pre-seismite
sample, which is a type A speleo-seismite.
71

4. A seismic event at ~29.1(±3.3)ka is based on a well constrained type A
speleo-seismite (DN-48 pre and post samples) and is corroborated by four
other pre- and post-seismite samples from around the cave.
5. A seismic event at ~38(±2.7)ka is based on a well constrained type A speleoseismite
(DN-44 pre and post dated samples) and is corroborated by six other
post- and pre-seismite samples from around the cave.
6. A seismic event after ~57.9(±5.2)ka is based only on pre-seismite samples,
usually of type C. Its isochron plot is scattered and gives a high error on the
calculated age. It is still considered an indicator for a seismic event, which
occurred after that time, since it is based on six different speleo-seismites from
around the cave.
7. A seismic event at ~137(±29)ka is based on five pre and post seismite samples
from around the cave. Most of those samples are from type C speleo-seismites.
The age calculation is based on sample ages with large errors and is therefore
less reliable.
8. A seismic event at ~147.6(±5.4)ka is based on four type A pre and post
seismite dated samples from around the cave. The age calculation yielded a
minimal scatter isochron plot.
9. A seismic event at ~160(±45)ka is based on five pre and post seismite dated
samples from around the cave. Three of those samples are type A speleoseismites.
The age calculation is based on sample ages with large errors and is
therefore less reliable.
5.2 Comparison of results with other paleoseismic studies
One way to verify if the accuracy of ages obtained are valid as seismites is to correlate
them to known, well established ages of seismic events (e.g. Kagan et al., 2005). As noted
above, data on paleoseismic ac<strong>tivity</strong> on the CF are scarce and often not very accurate and
there is no clear evidence of historically known earthquakes. Nevertheless, some
information is available (Table 8 and Fig. 40) Since Mt. Carmel is at a similar distance
from the DST as Soreq Cave is (Kagan et al, 2005), an initial comparison of the ages
obtained from Denya Cave seismites to ages obtained from DST paleoseismic studies, is
made (Table 8 and Fig. 40). The comparison showed some matching ages. If such is the
72

case, it is not clear which of those two fault systems caused damage to speleothems
analyzed from Denya Cave.
The sample age cluster at ca. 5ka from Denya Cave may correlate well to the seismic
event which caused structural damage to the EB I temple at Megiddo (Marco et al., 2006)
as well as to six damaged speleothems dated to that approximate time (4.9-5.7ka or older)
at Soreq cave in the Judean Hills (Kagan, 2002).
A seismic event at ca. 10ka is very clearly documented in Denya Cave speleoseismites
but is too old to be observed in Megiddo, which has no archeological evidence
from that period. That age might also be too young to be noted in paleoseismic trenches,
which were dug along the CF in the Kishon Valley, since most of the upper layers in that
area may have been disturbed by human ac<strong>tivity</strong> (Zilberman et al., 2006). This event was
not recorded at all in Soreq Cave as well. It might have been recorded in two
paleoseismic trenches in the area of Ein-Gev, along the northern segment of the DST,
which were dated to ca. 11ka (Amit et al., 2009).
The seismic event recorded in Denya Cave speleothems at ca. 21ka might be
supported by the age of the upper part of the shutter ridge dated by Zilberman et al.
(2006) to 24.5±2.5ka, which was followed by an incision of the stream channel and
assumed to be indicative of fault movement.
A seismic event at ca. 29ka, obtained from Denya Cave speleothems, might be
supported by the ages obtained for a layer in a paleoseismic trench along the Nesher fault,
which indicates a termination of a 50ka long subsidence, dated to 27±1ka (Zilberman et al.,
2006).
The well constrained age of ca. 38ka for a seismic event, which affected Denya Cave,
could probably be supported by three different paleoseismic findings. The first, an event
reported by Kagan et al. (2007) at ~39±1 ka, which has left evidence of brecciated marls at
four Lake Lisan sites along the Dead Sea basin as well as five well-constrained collapses in
different areas of the Soreq cave. Another one is a stratigraphic step in a paleoseismic
trench along the CF, which was dated to 32±4.4ka, and indicated that the faulting occurred
before ca. 35ka (Gluck, 2002). And the last is the dated layers to ca. 37ka in two
paleoseismic trenches in Ein-Gev (Amit et al., 2009).
The age cluster of ca. 58ka is based on pre-seismic event samples from Denya Cave,
which indicates that a seismic event occurred sometime after. This age might possibly be
supported by three collapses dated in Soreq cave speleo-seismites, and Lake Lisan
brecciated marls at three sites, which all yielded an age of 52±2.
73

The sample age cluster of ca. 137ka may possibly be supported by the age obtained
for a post collapse growth on a ceiling block, dated in Har-Tuv cave to be younger than
135ka (Kagan, 2002).
The age cluster of ca. 148ka was obtained from only four dated samples.
Nevertheless, it is corroborated by dated speleothem samples from Har-Tuv and Soreq
caves, which yielded ages between 144 and 155ka (Kagan, 2002). It might also be
corroborated by the age of material from the base of the shutter ridge studied by Zilberman
et al. (2006), which was dated to 146±20ka. It should be noted that the error margin for that
age is much larger than that of the age cluster from Denya Cave (147.6±5.4).
Although the age cluster that was determined by Denya Cave seismite samples at
160±45 has a large error, it might nevertheless be compared to the age, reported by
Zilberman et al. (2006), for a layer in a paleoseismic trench, which indicated subsidence of
a small basin south of the main fault, and was dated to 176±30ka. A collapsed pillar in
Soreq cave yielded a post-seismic age of ca. 163ka, and might also be compared to this age
cluster.
Ages obtained for Denya Cave age clusters can potentially be compared to other ages
from paleoseismological findings in Israel. The likelihood that this correlation is random
can be estimated by randomly picking age ranges from the interval of the entire record,
namely 0-206 ka. Each of the Denya Cave dated events cumulatively occupy a finite time
range, and the chance for it to correlate at random with the time occupied by other records
is given by the ratio between the latter (total=149.9ky) and the range of dated time
(204.1ky). Each separate event dated by Denya Cave speleo-seismites has a ~70% chance
of randomly correlating to one of the other ages dated by different studies. For all nine
dated events to correlate, this figure needs to be raised by the power of nine events recorded
in Denya Cave (i.e. {[149.9/204.1]^9}*100), giving a ~6% chance. Those numbers
consider the errors on the given ages, which are higher for most of the ages older than
100ka. The same estimation was done for the likelihood that the six age clusters, which
yielded younger ages than 100ka, dated from Denya Cave speleo-seismites could all
randomly be correlated to other dated seismic events. It was found that for there is a ~3%
chance of that to happen (i.e. {[49.9(time occupied by other dated events)/88.1(the range of
dated events)]^6}*100).
These results further enforce that age clusters obtained from Denya Cave speleoseismites
are not random, and are indicators of seismic events. This comparison also
74

indicates that there is a possibility that some of those events might have originated from the
DST and not the CF.
Table 8: Comparison between Denya Cave cluster results and other paleoseismic studies in the
region. Blue-CF studies. Red-DST studies. Carmel 1: Zilberman et al., 2006; Carmel 2: Gluck,
2002; Megiddo: Marco et al, 2006; Soreq: Kagan, 2002 and Kagan et al., 2007; Ein-Gev: Amit,
2009.
Denya Carmel 1 Carmel 2 Megiddo Soreq Ein-Gev
2.3 ±0.4
3.5 ±0.4 3.15 ±0.15 3.9 3.5 ±1.4
4.8 ±0.8 5.25 ±0.25 5.3 ±0.3 5.7 ±2.2
9.2 ±1.9
10.42 ±0.69 11
13.25 ±0.25
20.8 ±3
24.5 ±2.5
29.1 ±3.3 27 ±1
35+
38 ±2.7 39 ±1 37
46.5 ±2
52 ±2
57.9 ±5.2
71 ±2
78 ±8 80 ±10
137 ±29 135+
147.6 ±5.4 146 ±20 149.5 ±5.5
160 ±45 176 ±30 163+
75

a
b
Figure 40: Comparison between Denya Cave cluster results and other paleoseismic studies in the region.
Blue marks indicate CF studies. Red marks indicate DST studies. Carmel 1: Zilberman et al., 2006;
Carmel 2: Gluck, 2002; Megiddo: Marco et al, 2006; Soreq: Kagan, 2002 and Kagan et al, 2007; Ein-Gev:
Amit et al., 2009).
76

5.2.1 Considerations for comparisons between paleoseismic studies
Although a multi-archival approach is probably the best way to validate the findings
from cave deposits, it is important to consider some additional aspects of the different
research techniques and their results. Speleoseismic research is based on an assumption
that earthquake-related damage can occur to speleothems in a cave that is in the vicinity
of an active fault and not necessarily on it. A damaged speleothem can therefore be an
off-fault type indicator of paleo-earthquakes as well as an on-fault indicator similar to
trenches across a fault trace. Whereas the former records ground accelerations, the latter
records ground rupture.
Paleoseismic trenches are usually dug perpendicular to a known or suspected fault
strand in order to determine the slip vector, and if possible date the slip events. The
accuracy of the findings depends on the type of fault and the types of soil investigated.
The studies cited in this research (Gluck, 2002; Zilberman et al., 2006) detected mainly of
earthquake proxies, such as a shutter ridge or subsiding formations. For the most part the
ages were of general tectonic phenomena such as the beginning or termination of
subsiding through the accumulation of soil in depressions, which are difficult to compare
with the ones yielded from speleo-seismites. It is therefore essential to make the
comparison between the different studies while taking into consideration their inherent
differences.
Lacustrine sediments from fault basins (e.g. Lake Lisan aragonites), which are also
on-fault seismic indicators, could be highly sensitive to any ground acceleration and
could therefore potentially record very small events. By comparison, off-fault caves
would only be damaged by strong events if they are located far from an earthquake
epicenter. If a cave is close to the fault it might record smaller events, which could
damage some of the smaller types of speleothems, but such samples are difficult to date
and are usually highly suspect because of their fragility.
Furthermore, results obtained from dating damaged speleothems indicate time
constraints of a likely event that caused the damage. When such constraints are from both
pre- and post-seismite samples, both yielding similar ages (within the error margin), they
are considered the age of an event. That age, though potentially having an analytical error
of less than 1%, is still not an exact date as would be given by historical, archeological or
even some lacustrine sediment evidence (Migowski et al., 2004). Only by comparing the
77

ages obtained through speleo-seismites to known earthquakes can a specific event be
determined as the cause for damage in karstic caves.
5.1.2 Suggestions for further research
Although mechanisms of structural damage to speleothem formations and cave
environments are not fully understood, it is still reasonable to assume that damage
depends to a great deal on the location of a cave and its distance from an earthquake
epicenter. Denya Cave is located on a spur sloping down to the west of Mt. Carmel, and
as noted above, this area is quite close to the CF system and has many seismic features
(ch. 1.4.2). It seems likely, therefore, that those features are connected to the fault system
and are activated by it, especially since there are no tectonic features on the west side of
the mountain chain. An in depth investigation of the structural features of the northwestern
Carmel might shed some light on the tectonic mechanisms in that area and
perhaps also on likely mechanisms that created the kind of structural features observed in
Denya Cave.
Another consideration that could indicate the source of seismic events recorded in
Denya Cave is in models for seismic loading, as conducted by Marco et al. (in prep.).
Those scholars assessed potential sources for earthquakes that might have caused damage
to the archeological site of Megiddo (Fig. 1). In their model they adopted a slip rate of
0.5mm/y along the CF and then considered three alternatives for estimating the
distribution of that slip along the CF. One of those alternatives suggests that a strong
earthquake (magnitude of 7.2) which ruptured the entire fault (~90km) is consistent with
observed offsets of stream channels reported by Achmon (1986). These scholars’ analyses
showed that that kind of earthquake could be characteristic of the CF if it had a recurrence
interval of several millennia. That seems to be consistent with the findings from Denya
Cave (see ch. 4.3- Seismic events in Denya Cave).
Marco et al. (in prep.) also compared spectral accelerations expected from ruptures
along the two fault systems at Megiddo, given a certain magnitude of earthquake and its
appropriate recurrence. The comparison led them to suggest that the dominant hazard at
the site comes from the CF. However, that conclusion was based on an assumption that
the slip was accounted for largely by moderate earthquakes (examined for a maximum
magnitude M5.5 using the Gutenberg-Richter frequency-magnitude distribution). They
also noted that if that were the case it would be hard to reconcile it with evidence for
surface rupture (Achmon, 1986). On the one hand that observation establishes a
78

easonable assumption that whatever the cause of seismic event recorded in Denya Cave,
it is most probable that it originated from the CF rather than from the DST. Yet it also
signifies that the findings from Denya Cave are not necessarily attributed to the CF. It is
therefore evident that further studies are needed to reconcile these problems.
6. Conclusions
This study successfully established that broken and deformed cave deposits in Denya
Cave on Mt. Carmel are speleothem seismites. By using U-Th dating methods these
seismites were dated in order to extend the paleo-earthquake record for the CF.
1. Broken speleothems, collapsed structures and cracks observed in Denya Cave,
appear to be evidence of seismically induced damage. The exclusion of nonseismic
causes for damage in Denya Cave, as well as various assessments as to
seismic ac<strong>tivity</strong> throughout the Carmel region, affirms the likelihood of
earthquake damage.
2. Samples of broken or deformed speleothems from Denya Cave were mapped
and analyzed. Where a break or deformation of speleothems was detected a
seismic contact was identified. Material was extracted by means of a hand held
pneumatic drill from laminae located as close as possible to the seismic contact.
The last lamina preceding the break event was termed a pre-seismic sample,
while the first one to succeed the break event was termed a post-seismic sample.
All samples were dated with the uranium decay series method. The samples
were extracted from laminae closest to the seismic contacts, allowing for the
closest age constraints to seismic events.
3. A classification method for different types of seismites was added to speleoseismite
analysis in order to determine the reliability of the results.
Classification was determined according to the type of speleothem, the clarity of
the seismic contact as a viable indicator for a seismic event, and the ability to
adequately sample material. Type A seismites show clear breaks, which indicate
abrupt events. Type B seismites show noticeable changes in sedimentation
patterns, which might be related to abrupt events. In both types pre- and post-
79

eak phases yielded datable samples. Types C, D and E yielded only pre- or
post-break datable samples (i.e. they indicated only one sided constraints on
seismic events). Type C seismites are considered robust indicators of seismic
events as are type D seismites, yet seismites of type D are harder to sample due
to fragments of un-datable material embedded in them. Type E seismites are
fragile stalactites, which are less indicative of seismic events, and therefore their
ages can only be used as corroborative evidence when they are part of a cluster
of samples that have yielded similar ages.
4. A total of 68 speleothem samples was taken and inspected from Denya Cave, 37
of which were identified as seismites; of them, 32 were processed. Ten seismites
are severed stalagmites broken along sub-horizontal plains. Nine seismites of the
32 are severed stalactites of different shapes and sizes. The remaining seismites
are flowstone samples in which breaks and depositional unconformities were
found; some revealed soda straw speleothems embedded in them.
5. U-series age equations are based on the assumption that all 230 Th in the sample
is the product of 234 U decay. Most speleothem samples contain 230 Th, which is
associated with a detrital component that becomes cemented or occluded within
a speleothem. The extent of detrital Th contamination can be monitored by
232 Th, using as a first estimation the ratio 230 Th/ 232 Th. The lower this ratio, the
higher the probability that a detrital 230 Th component exists in the sample,
causing its age to appear older than it is. For most speleothem samples from
Denya Cave a correction for detrital 230 Th was needed.
6. A correction factor for speleothem ages can be determined using the detrital
molar ratio of 232 Th/ 238 U. The most common correction factor for crust value
rocks is 3.8. In a carbonate terrain (e.g. Judean Hills), this correction factor was
determined as 1.8. Correction factors for detrital Th were calculated for ages of
speleothems from Denya Cave, using isochron calculations of isotopic ac<strong>tivity</strong>
ratios for ( 232 Th/ 234 U) vs. ( 230 Th/ 234 U) isochrons. These calculations yielded
different correction factors for different sets of isochrons, all of them extremely
low (between ~0.1-~0.7). These different factors are assumed to be indicative of
more than one phase or origin of detrital matter. It was therefore not possible to
80

establish a unique correction factor for Denya Cave detrital 230 Th. Further
analysis suggested that these low correction factors might indicate the existence
of hydrogenous Th in the speleothems of this cave. It is assumed that the
hydrogenous Th does not overly affect the ages reported in this study, but the
degree of its affects was not established.
7. The ages obtained for Denya Cave seismite samples were corrected for detrital
Th using an isochron method based on Osmond type isochrons by means of the
Isoplot3.7 program. Using the U-series evolution diagram, where x= 230 Th/ 238 U
y= 234 U/ 238 U, a third axis is added, z= 232 Th/ 238 U, in order to calculate a
regression line for an isochron (samples of the same age). The x-y intercepts of
this three dimensional isochron define the ratios used to calculate a 230 Th/U age
and initial 234 U/ 238 U. Denya Cave seismite samples, which were considered to
be of the same age when certain criteria were met, were plotted along isochron
lines and a single age was determined for them. Criteria for plotting seismite
samples along isochron lines are based on the amount of detrital matter within
the dated sample, structural features within the cave and stratigraphic
considerations in the sample laminae.
8. The isochron calculated ages obtained for groups of speleo-seismite samples
indicate that each group records a seismic event. Nine age clusters were
determined for speleo-seismites from Denya Cave, indicating the ages of
seismic events which affected the cave over the last 200ky: 4.8±0.80ka;
10.42±0.69ka; 20.8±3.0ka; 29.1±3.3; 38.0±2.7ka; 57.9±5.2ka; 137±29ka;
147.6±5.4ka and 160±45ka.
9. A comparison with data available to date from other paleoseismic studies in the
region shows that all ages obtained for Denya Cave age clusters can potentially
be compared to other ages obtained from paleoseismological studies in Israel.
The comparison indicates that the breaks identified in Denya Cave speleothems,
are not random and lends supportive evidence to the assumption that they
represent seismic events.
81

10. Some of the ages obtained from this study might coincide with ages of seismic
events dated along the DST, as well as those along the CF. Therefore, further
studies are needed in order to determine which of those two fault systems
created the seismic events reported in this study.
82

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87

Appendix I: Denya Cave samples; summery of types,
locations and dated samples.
a. Table of Denya Cave speleothem samples
b. Seismite sample photographs
c. Digital photos of Denya Cave and samples

I-a. Table of Denya Cave speleothem samples
Table 1: Denya Cave sample I.D.'s. Samples marked in red are spleo-seismites.
Sample Area Seismic Processed Lab fig. i.d’s Comments
i.d. in map contact
DN-1 A No No
DN-2 A Yes Yes 1,2,3,4
DEN-2 A Yes Yes pre
DN-3 A No No No calcite
DN-4 A Yes Yes pre I, II (post), III, top &
Isochrons 1, 2
DN-5 B No No
DN-6 C Yes Yes a-pre (post), b-pre, c-pre I,
II, III,IV,V
DN-7 C Yes Yes 45-pre, 46-post I, II, pre,
post I, II, 47-post
DN-8 B No No
DN-9 C Yes Yes pre, pre-down, pre-bottom,
pre (post)
DN-10 B No No No calcite
DN-11 B Yes No Not enough material
DN-12 B Yes No Not enough material
DN-13 B Yes No Not enough material
DN-14 B Yes Yes a: pre I, PRE-I
DN-16 A No No Isochron
DN-17 A Yes Yes pre, post
DN-18 A No No No calcite
DN-19 A Yes Yes pre I, II
DN-20 A No No
DN-21 B Yes No pre I, II
DN-22 B Yes Yes pre I, II, post I, II
DN-23 B No No
DN-24 B No No
DN-25 B Yes Yes post I, II
DN-26 B Yes Yes top: pre I, post I, II
DN-27 B Yes Yes post II
DN-28 B No No
DN-29 B No No
DN-30 B No No
DN-31 B No No
DN-32 A No No
DN-33 A Yes Yes c1-pre, post, c2-pre, post
DN-34 B Yes Yes a: pre I, II, III
DN-35 B No No Isochron
DN-36 B Yes Yes pre I, II, III, post I, II
DN-37 B Yes Yes a: pre, post
DN-38 B No No
DN-39 B Yes No Very large detritic
component
DN-40 B Yes Yes pre- I, II, post I Age reversal
DN-41 B No No
DN-42 B Yes Yes e-pre, post
DN-43 B Yes No Not enough material
DN-44 A Yes Yes pre, post
DN-45 A Yes Yes pre, post
DN-46 A Yes Yes pre I, II, post Age reversal

DN-47 A Yes Yes pre I, II, post I
DN-48 A Yes Yes pre, post
DN-49 A No No
DN-50 A No No
DN-51 A Yes Yes pre I-IV, post I
DN-52 A Yes Yes pre, post
DN-53 A No No Isochron
DN-54 A No No
DN-55 A No No
DN-56 A No No
DN-57 A No No
DN-58 A No No
DN-59 A No No
DN-60 A No No
DN-61 A No No
DN-62 A Yes Yes pre I, II, post II & Isochron
DN-63 A Yes Yes pre I, II, post
DN-64 A No No
DN-65 A Yes Yes pre, post
DN-66 A Yes Yes b-pre, c-pre I, II, III, post I
DN-67 A No No
DN-68 A Yes Yes pre

DEN-2
Sample DEN-2 is a type C-1 seismite. It was
found not in situ in the cave.
C-1
pre
21.62ka

DN-1 DN-2
Seismic contact
DN-2
Sample DN-2 is a stalagmite connected to the
broken stalagmite DN-1(type C-1). The
assumption is that the seismic contact is the
contact between the two stalagmites (between
sampled laminae 2 and 3 or 4). Another seismic
contact might be where the laminae of DN-2 start
to form fully horizontally (marked by dotted green
lines), since this is where they are unquestionably
not broken.
A-1
DN-1
2-pre
13.79ka
4-post
6.28ka
Seismic contact
3-post
5.3ka

DN-4
Sample DN-4 is a type C-1
seismite.
Seismic contact
(4) pre-top
16.72ka
(1) pre I
24.34ka
(2) pre II
19.98ka
C-1
(3) pre III
(post)
20.14ka
Seismic contact

pre
59.94ka
DN-6
Samples DN-6 a, b and c are all taken from broken bedrock covered with
speleothems which fell from the cave wall. The scar on the wall is still evident
which indicates the direction of the fall as well as enhancing the probability of the
break being caused by a seismic event (type C-3). The pre-break samples
indicate the last laminae deposited as stalactites before they broke off.
C-3
Seismic contact
pre
18.07ka
b
Seismic contact
pre
16.75ka
Seismic contact
pre II
35.37ka
pre I
22.32ka

DN-7
DN-7 appeared to be a stalagmite which was
slightly broken on top. When cut into sections it
became clear that the top of it was merely
eroded. Yet inside, an angular unconformity is
clearly visible which indicates that an event
occurred which broke the top of the stalagmite,
causing an hiatus of deposition. The
unconformity is considered to be the seismic
contact, making it a type A-1 seismite.
46-post
12.21ka
Seismic contact
45-pre
33.2ka
46b-post
9.18ka pre
24.51ka
A-1
Seismic contact
post
12.21ka
post B
11.05ka

DN-9b
DN-9b is a type C-1 seismite.
Sample (1) was thought to
represent a post-break stage but
in fact is the last lamina deposited
before the break.
(1)pre (post)
11.17ka
(2)pre (bottom)
12.1ka
Seismic contact
C-1
(3)pre (down)
10.04ka

DN-11, 12 and 13
These samples are broken stalactites indicate a phase of re-growth
and therefore might be seismite samples. However, they are not
robust indicators of seismic events since they are very fragile and
the re-growth phase is from currant drip water. They were therefore
discarded.
E-1

DN-14
DN-14 is a type C-1 seismite.
Seismic contact
C-1
Seismic contact pre
64.8ka

Seismic contact
pre
12.51ka
DN-17
DN-17 is a type A-1 seismite.
The post sample is mainly
detrital matter, therefore the age
it yields requires a correction.
post
10.35ka
A-1

DN-19
DN-19 is a type C-1
seismite.
pre I
49.83ka
pre II
23.32ka
C-1
Seismic contact

DN-21
DN-21 is a type C-1 seismite.
pre I
32.42ka
pre II
54.35ka
C-1
Seismic contact

DN-22
DN-22 is a flowstone core of a type A-4
seismite.
A-4
post II
163.7ka
post I
394.92ka
pre I
Eq.
Seismic contact
pre II
395.93ka

DN-25
DN-25 is a sample of flowstone on
bedrock from the edge of a cavity in
the cave floor next to an area of
collapsed stones.
No indication of a seismite was
found in this sample.
post II
80.3ka
post I
136.5ka
D-2

DN-26
DN-26 is a flowstone core of a type
A-4 seismite.
A-4
Seismic contact
Seismic contact
pre I
Eq.
post I
250.04ka
pre II
post II

DN-27
DN-27 is a sample of
flowstone on bedrock from
the edge of a cavity in the
cave floor next to an area
of collapsed stones. It is a
type D-2 seismite.
D-2
post I
Seismic contact
post II
207.66ka

Seismic contact
DN-33
DN-33 is a group of broken stalactites
from the cave ceiling in chamber A, in
which the whole floor is strewn with
fallen rocks. All of them are type A-1
seismites.
A-2
Seismic contact
post
post
0.47ka
134.38ka pre
43.24ka
pre
146.54ka

DN-34
DN-34 is a flowstone core
of a type A-5 seismite.
A-5
Seismic contact
Seismic contact
pre I
158.94ka
DN-34a
post
112.22ka
pre III
331.79ka
pre II
146ka

A-4
Seismic contact
post I
253.64ka
pre I
325.38ka
DN-36
DN-36 is a flowstone core of a type A-
4 and A-5 seismites. Sample pre III is
a loose broken stalactite found while
drilling and is a type E-1 seismite.
Seismic contact
A-5
pre III
42.96ka
E-1
post II
146.26ka
Seismic contact
pre II
154.47ka

DN-37a
DN-37a is a flowstone core in which D-1 and D-2 type seismites were found.
Seismic contact
pre
30.72ka
post
178.98ka
D-2
Seismic contact
D-1

DN-39
This coral type speleothem was
located along a wall surrounding a
crevice. It was not possible to
separate enough datable material
from the surrounding bedrock,
therefore no samples were dated.
D-2

DN-40
DN-40 is a sample of
flowstone on bedrock from
the edge of a cavity in the
cave floor next to an area
of collapsed stones. It is a
type B-2 seismite as well
as a type C seismite in
which a pre-crack sample
was dated.
Seismic contact
pre II
53.72ka
crack
pre I
240.83ka
C-1
B-2
Seismic contact
post I (2)
296.2ka

DN-42
DN-42 is a group of broken stalactites
from the cave ceiling in chamber B
above the small rock fall. Sample 42e
is a type A-1 seismites.
Seismic contact
A-2
pre
311.28ka
post
0.77ka

DN-43
This stalactite was located close to broken
speleothems and was found to be a seismite. It
was not possible to separate enough datable
material from the surrounding bedrock, therefore no
samples were dated.
D-2

DN-44
DN-44 is a flowstone core
of a type A-4 seismite.
A-4
post
38.37ka
pre
38.58ka
Seismic contact

Seismic contact
DN-45
DN-45 is a type A-1 seismite.
The post sample is mainly
detrital matter, therefore the age
it yields requires a correction.
post
23.97ka
pre
29.18ka
A-1

pre II
149.02ka
A-3
DN-46
DN-46 is a flowstone core of flowstone cementing
rock and speleothem fragments. The samples
dated were of a type A-3 seismite (the pre samples
being two broken stalactites).
Seismic contact
post
174.54ka
pre I
136.13ka

DN-47
DN-47 is a flowstone core of a type A-4 seismite.
Sample pre II is a loose broken stalactite found while
drilling and is a type E-1 seismite.
pre I
50.09ka
post I
37.14ka
pre II
23.49ka
E-1
Seismic contact
A-4

DN-48
DN-48 is a flowstone core of a
type B-1 seismite. It was taken
from the edge of a pool. A
possible mechanism which
could explain the depositional
unconformity could be that the
pool on the edge of which the
tilted laminas were deposited
was suddenly filled with debris
during a seismic event. This
could have caused the
subsequent laminae to be
deposited horizontally.
B-1
post
26.83ka
pre
28.53ka
Seismic contact ()

DN-51
DN-51 is a stalactite formation
from the cave wall. Samples
pre-II & III are from broken
stalactites. Samples pre & post I
might are in fact seismites of
two different events: pre I- is
post seismic contact. Post I is
nearly the last lamina before a
small break in the stalactite and
therefore not a seismite.
post I
(maybe pre)
59.05ka
pre I
(maybe post)
131.35ka
A-2
Seismic contact
pre II
8.31ka
A-4
E-1
pre III
4.89ka

DN-52
DN-52 is a flowstone
core of a type A-4
seismite.
A-3
pre
55.69ka
post
43.52ka
Seismic contact

DN-62
DN-62 is a flowstone sample of type A-4 and D-2
seismites. The D-2 seismite might have yielded a
mixed age with the bedrock.
A-4
post I
253.34ka
pre I
Eq.
Seismic contact
D-2
post II
207.85ka

pre II
39.12ka
crack
post
29.7ka
pre I
66.78ka
Seismic contact
DN-63
DN-63 is a flowstone sample of type A-5
seismites which was found as only partially
connected to the cave flowstone because
of a crack.
A-5

DN-65
DN-65 is a flowstone sample of type A-4 seismites.
pre
340.8ka
Seismic contact
post
301.5ka
A-4

pre
139.65ka
E-1
Seismic contact
pre II
320.3ka
post II
60.53ka
pre III
9ka
DN-66
DN-66 are a stalagmite
and stalactites. DN-66b
is a type E-1 seismite
and DN-66c has two type
A-2 seismites.
A-2
pre I
92.16ka
post I
16.85ka

Seismic contact
DN-68
DN-68 is a a fallen broken stalagmite
buried in the debris of chamber A
yielding a type A-4 seismite.
C-1
pre
36.52ka

Appendix II: Laboratory protocols and MC-ICP-MS
function
II-a. Laboratory protocol for the separation of U and Th for
measurement with the MC-ICP-MS
A chromatographic separation of Uranium and Thorium
Preparations:
• Weighing ~0.3g of material with a uranium concentration of about 0.2-
0.3 ppm.
• Dissolving the samples with 7N of HNO 3 acid in centrifugal test tubes.
• The remaining insoluble material is separated with centrifuge and
transported to a separate Teflon container.
• A spike ( 236 U- 229 Th) is added and measured and then the sample is left
until equilibrium is reached.
• The solution is evaporated and then another 7N of NHO 3 is added and
a clear solution is received.
• The insoluble material is dissolved with 5ml of a mixture of
concentrated HF and HNO 3 .
• The detritic, insoluble matter is added to the solution.
• The solution is evaporated and more 7N HNO 3 is added
Chromatographic separation:
• Resin (Ag 1 x 800 200-400 mesh) is added to colons which are then
washed twice with 6N of HCl and three times with distilled water (TD
H 2 O).
• Preconditioning the colons to the solution by washing them with
HNO 3 .
• Adding the samples to the colons and washing them with 7N HNO 3
three times.
• Preconditioning the colons to thorium collection using 6N HCl.
• Adding 3.5ml of 6N HCl to the colons and collecting the thorium in
Teflon containers.
• Preconditioning the colons to uranium collection using 1N HBr.
• Adding 3.5ml of 1N HBr to the colons and collecting the uranium in
Teflon containers.
• Evaporation of the separated solutions until they are completely dry.
• Adding 2-3ml of 0.1N HNO 3 to the uranium in the Teflon containers
and moving it to centrifugal test tubes.
• Adding 5ml 0.1N HNO 3 to the thorium in the Teflon containers and
moving it to centrifugal test tubes.
• Measuring the concentration of uranium in the samples from the
solution with the ICP-MS.
• Diluting the samples with a high concentration (more than the standard
50ppb).
• Adding 25µl of standard 112a U NBL, in which the 234 U/ 238 U is
known, to the thorium test tubes.

II-b. Laboratory protocol for the preparation of samples for
chromatographic separation of U and Th without the
insoluble/detrital matter
Preparations:
• Weighing of material.
• Dissolving the samples with twice the molar ratio of DH 3 COOH acid
in centrifugal test tubes:
CaCO 3 + 2CH 3 COOH = Ca(CH 3 COO) 2 + H 2 O + CO 2
• The insoluble material is separated with centrifuge (not more than 40 cc
per run) for 20 minutes at 4000 cycles per minute.
• The solution is separated into a Teflon container.
• After cleaning the test tubes with 5 cc of distilled water, while going
over the sides with a pipette and shaking the tube, repeating the
centrifuge procedure twice more.
• Removing the remaining solution with a 5 cc pipette to a new test tube.
• Adding and measuring spike ( 236 U- 229 Th) into the new test tube.
• Adding the contents of the new test tube to the Teflon container with
the rest of the solution, cleaning it out with distilled water.
• The solution is evaporated to complete dryness, making sure no acetic
acid remains.
• Continuing chromatographic procedure as stated above.
II-c. Measuring isotopic ratios using the ICP-MS
MC-ICP-MS: Multiple Collector Inductively Coupled Plasma Mass Spectrometer
(produced by U.K. Nu Instrument) in the Geological Survey.
The different isotopic ratios are determined by the injection of sample solutions in
Aragon Plasma (~6000 o K) which produces an ionization of nuclides which are then
accelerated in an electrical field, then separated with a magnet and are measured by
the mass spectrometer (Goldstein and Stirling, 2003). The machine contains 12
Faraday detectors and 3 Ion Counters (IC). The IC is used for very low concentrations
of 229 Th, 236 U, 230 Th, 234 U.
Measuring uranium ratios:
This is done in three cycles the following ratios are determined: 235 U/ 236 U,
235 U/ 238 U and 234 U/ 236 U.
• Cycle I - The conditions of the machine are determined by the
measuring of 235 U/ 238 U with the Faraday detector. The results are
calibrated using the known ratios which exist in nature. Then a
calibration is done for the IC0 detector.
• Cycle II - Faraday detectors measure 235 U and 238 U and the results are
calibrated for the IC1 detector.

• Cycle III - Faraday detectors measure 235 U and 238 U, 236 U is measured
with the IC0 detector and 234 U is measured with the IC1 detector.
Measuring thorium ratios:
This is done by calibrating the ratios: 232 Th/ 229 Th and 230 Th/ 229 Th to uranium
isotopic ratios due to the configuration of the machine does not allow for a
direct measurement of 230 Th.
• Cycle I – Faraday detectors measure 235 U and 238 U and the results are
calibrated for the IC1 detector in which the 229 Th is measured.
• Cycle II – IC1 detector measures 235 U and Faraday detectors measure
235 U.
• Cycle III - Faraday detectors measure 235 U and 238 U and the results are
calibrated for the IC1 detector in which the 230 Th is measured.
238 U/ 235 U is constant in nature and in the spike 236 U- 229 Th is known, allowing
for an accurate measurement of 238 U/ 234 U and 230 Th/ 234 Th.

Appendix III: All seismites considered for age clusters devided into seismic events.
Event 2 Event 3
Pre I Pre II Pre III Pre IV Pre V Post I Post II Post III Post IV Pre I Pre II
Post I Pre I
Sample
Name Age (+) (-) Name Age (+) (-) Name Age (+) (-) Name Age (+) (-) Name Age (+) (-) Name Age (+) (-) Name Age (+) (-) Name Age (+) (-) Name Age (+) (-) Name Age (+) (-) Name Age (+) (-) Name Age (+) (-) Name Age (+) (-)
DEN-2 DEN-2 pre 21619 390 -388
DN-2 DN-2-2 13802 362 -361 DN-2-3 5296 250 -250 DN-2-4 6285 227 -227
DN-4 DN-4 pre (top) 16717 214 -214 DN-4 pre II (post) 20132 362 -361 DN 4 pre 19981 175 -175 DN3y(dn4-pre) 24343 364 -362
DN-6a DN 6A pre (post) 59936 416 -415
DN-6b DN 6B pre 18079 304 -304
DN-6c DN8y(dn6C pre) 16749 355 -354 DN 6C pre 34300 352 -352 DN-6c pre I 22317 276 -276 DN7y(dn6C pre) 35921 483 -481 DN-6c pre II 35363 354 -354
DN-7 DN 7 pre 24511 198 -198 DN-7-45 33202 245 -245 DN 7 post 12206 150 -150 DN 7postB 11050 80 -80 DN-7-46b-post 9181 196 -196 DN-7-47 10464 160 -160
DN-9 DN9y(dn9b prebottom) 12097 542 -538 DN6y(dn9B post) 11165 346 -345 DN 9B pre 55394 488 -486
DN-14 DN-14A-PRE-I 64801 517 -516 DN-14a-preI 73220 890 -882
DN-17 DN-17-PRE 12515 654 -650 DN-17-POST 10346 129 -129
DN-19 DN-19-PRE-I 49829 762 -756 DN-19-PRE-II 23323 425 -423
DN-21 DN-21pre-I 32420 387 -386 DN-21 pre II 54345 457 -456
DN-22 DN-22-PRE-I eq. 2658 -2590 DN-22-PRE-II 395927 22847 -18817 DN-22-POST-I 394924 24176 -19364 DN-22-POST-II 163707 2507 -2446
DN-25 DN-25 post I 136503 14315 -12605 DN-25 post II 80306 738 -733
DN-26 DN-26top-preI eq. DN-26top-postI 250043 3850 -3717
DN-27 DN-27-II 207662 2776 -2702
DN-33 DN-33C1-PRE 43241 2094 -2055 DN-33c1-post 466 10 -10 DN-33c2-pre 146544 1674 -1644 DN-33c2-post 134388 1848 -1814
DN-34 DN-34a-pre I 158935 2155 -2108 DN-34a-pre II 146004 2253 -2203 DN-34a- post 112216 1264 -1247 DN34a-pre III 331793 13731 -12152 DN-34a- post 112216 1264 -1247
DN-36 DN-36 pre I 325384 7240 -6771 DN-36 post I 253643 7157 -6679 DN-36 pre II 154473 1861 -1824 DN-36 post-II 146262 1858 -2302 DN-36 pre III 42965 285 -285
DN-37 DN-37a post 178984 2362 -1790 DN-37a-pre 30719 211 -211
DN-40 DN-40-pre I 240828 4005 -3857 DN-40 post I (2) 296208 9310 -9456 DN-40-pre II 53717 6189 -5841 DN-40 pre-II 59897 2429 -2376
DN-42 DN-42e-pre 311281 9461 -8720 DN-42e-post 773 31 -31
DN-44 DN-44 pre 38577 707 -708 DN-44 post 38375 444 -442
DN-45 DN-45 pre 29176 1154 -1142 DN-45 post 23969 273 -273
DN-46 DN-46 pre I 136133 1017 -1008 DN-46 pre II 149020 2619 -2556 DN-46 post 174544 2862 -2784
DN-47 DN-47 pre I 50089 553 -550 DN-47 post I 37136 398 -396 DN-47 pre II 23494 246 -246
DN-48 DN-48 pre 28534 296 -296 DN-48 post 26820 203 -203
DN-51 DN-51 pre II 8307 271 -271 DN-51 pre III 4886 131 -131 DN-51 pre IV 12197 173 -173 DN-51 post I (pre) 59048 590 -587 DN-51 pre I (post) 131346 1171 -1158
DN-52 DN-52 pre 55692 488 -485 DN-52 post 43519 652 -647
DN-62 DN-62 pre I eq. DN-62 post I 253340 12464 -11197 DN-62 post II 207847 5571 -5291
DN-63 DN-63-pre II 39122 283 -283 DN-63-post 29701 225 -225 DN-63-pre I 66781 427 -426 DN-63-pre II 39122 283 -283
DN-65 DN-65 pre 340805 21364 -17886 DN-65 post 301492 10009 -9185
DN-66b DN-66b-pre 139648 12826 -11444 -1475
DN-66c DN-66c-pre I 92162 790 -785 DN-66c-post (I) 16849 1495 DN-66c-pre II 320296 17481 -15087 DN-66c-post II 60527 1080 -1069 DN-66c-pre III 9000 1495 -1475
DN-68 DN-68b-pre 36522 1185 -1171

Appendix IV: Isotopic ac<strong>tivity</strong> ratios of all seismite samples arranged by ages
Dated sample name 234/238 err 230/234 err 234/230 err 234/232 err 232/234 err 238/232 err 230/238 err 232/238 err 230/232 err Det. Age (y) + -
DN-33c1-post 1.06245 0.00216 0.004277 0.000094 233.806 5.147 1312.022 2.680 0.000762 0.000002 899.011 2.313 0.004544 0.000100 0.001112 0.000003 5.61 0.12 n 466 10 -10
DN-42e-post 1.05686 0.00153 0.007083 0.000283 141.187 5.637 2474.089 3.607 0.000404 0.000001 1932.721 7.177 0.007486 0.000299 0.000517 0.000002 17.52 0.70 n 773 31 -31
DN-51 pre III 1.04455 0.00108 0.043943 0.001155 22.757 0.598 230.947 0.242 0.004330 0.000005 205.144 0.807 0.045900 0.001208 0.004875 0.000019 10.15 0.27 y 4886 131 -131
DN-2-3 1.04588 0.00237 0.047547 0.002197 21.032 0.972 473.138 1.099 0.002114 0.000005 347.203 2.708 0.049728 0.002300 0.002880 0.000022 22.50 1.05 n 5296 250 -250
DN-2-4 1.04588 0.00152 0.056177 0.001970 17.801 0.624 300.532 0.446 0.003327 0.000005 244.022 1.420 0.058754 0.002062 0.004098 0.000024 16.88 0.60 y 6285 227 -227
DN-51 pre II 0.99870 0.01697 0.073535 0.002297 13.599 0.425 90.117 1.533 0.011097 0.000189 86.146 0.646 0.073440 0.002611 0.011608 0.000087 6.63 0.18 y 8307 271 -271
DN-66c-pre III 1.05658 0.00100 0.079475 0.001827 12.583 0.289 24.302 0.012 0.041148 0.000021 25.713 0.123 0.083972 0.001932 0.038891 0.000187 1.93 0.05 y 9000 1495 -1475
DN-7-46b-post 1.04368 0.00212 0.081000 0.001658 12.346 0.253 336.161 0.687 0.002975 0.000006 290.264 0.842 0.084538 0.001738 0.003445 0.000010 27.23 0.56 9181 196 -196
DN10y(dn9bpre down) 1.03678 0.00218 0.088197 0.003492 11.338 0.449 173.728 0.368 0.005756 0.000012 154.030 0.530 0.091441 0.003626 0.006492 0.000022 15.32 0.61 10036 418 -416
DN-17-POST 1.05396 0.00139 0.090817 0.001080 11.011 0.131 20.217 0.027 0.049464 0.000065 18.398 0.049 0.095718 0.001145 0.054353 0.000145 1.84 0.02 y 10346 129 -129
DN-7-47 1.05794 0.00108 0.091808 0.001339 10.892 0.159 417.196 0.429 0.002397 0.000002 364.203 0.886 0.097128 0.001420 0.002746 0.000007 38.30 0.56 10464 160 -160
DN 7postB 1.04236 0.00107 0.096677 0.000666 10.344 0.071 130.129 0.134 0.007685 0.000008 119.682 0.190 0.100773 0.000702 0.008356 0.000013 12.58 0.09 n 11050 80 -80
DN6y(dn9B post) 1.04874 0.00102 0.097639 0.002866 10.242 0.301 93.853 0.096 0.010655 0.000011 85.844 0.627 0.102398 0.003008 0.011649 0.000085 9.16 0.28 y 11165 346 -345
DN9y(dn9b prebottom) 1.03918 0.00137 0.105347 0.004444 9.492 0.400 121.631 0.166 0.008222 0.000011 109.215 0.727 0.109475 0.004620 0.009156 0.000061 12.81 0.55 n 12097 542 -538
DN-51 pre IV 1.03187 0.00268 0.106147 0.001422 9.421 0.126 42.628 0.111 0.023459 0.000061 39.931 0.172 0.109530 0.001495 0.025043 0.000108 4.52 0.06 y 12197 173 -173
DN 7 post 1.04360 0.00107 0.106243 0.001233 9.412 0.109 127.678 0.133 0.007832 0.000008 118.131 0.454 0.110876 0.001291 0.008465 0.000033 13.56 0.16 n 12206 150 -150
DN-7-46 1.05616 0.00145 0.106275 0.001341 9.410 0.119 211.184 0.291 0.004735 0.000007 190.966 0.452 0.112243 0.001425 0.005237 0.000012 22.44 0.29 12208 163 -163
DN-17-PRE 1.03993 0.00378 0.108770 0.005342 9.194 0.452 61.922 0.227 0.016149 0.000059 53.467 0.251 0.113114 0.005571 0.018703 0.000088 6.74 0.33 y 12515 654 -650
DN-2-2 1.05553 0.00227 0.119307 0.002928 8.382 0.206 87.118 0.189 0.011479 0.000025 73.174 0.293 0.125933 0.003102 0.013666 0.000055 10.39 0.26 13802 362 -361
DN-4 pre (top) 1.05119 0.00122 0.142647 0.001690 7.010 0.083 73.884 0.086 0.013535 0.000016 67.622 0.177 0.149949 0.001785 0.014788 0.000039 10.54 0.13 y 16717 214 -214
DN8y(dn6C pre) 1.05426 0.00116 0.142912 0.002799 6.997 0.137 43.323 0.048 0.023083 0.000026 39.133 0.179 0.150666 0.002955 0.025554 0.000117 6.19 0.12 16749 355 -354
DN-66c-post (I) 1.05186 0.00282 0.143690 0.011714 6.959 0.567 66.279 0.168 0.015088 0.000038 40.265 0.952 0.151142 0.012328 0.024836 0.000587 9.52 0.81 y 16849 1495 -1475
DN 6B pre 1.05783 0.00150 0.153364 0.002372 6.520 0.101 97.462 0.140 0.010260 0.000015 88.655 0.362 0.162232 0.002520 0.011280 0.000046 14.95 0.24 18079 304 -304
DN 4 pre 1.06953 0.00113 0.168137 0.001342 5.948 0.047 636.214 0.677 0.001572 0.000002 574.029 1.247 0.179827 0.001448 0.001742 0.000004 106.97 0.87 n 19981 175 -175
DN-4 pre II (post) 1.03404 0.00129 0.169149 0.002761 5.912 0.096 39.306 0.050 0.025442 0.000032 36.591 0.131 0.174906 0.002863 0.027329 0.000098 6.65 0.11 y 20132 362 -361
DEN-2 pre 1.02887 0.00097 0.180433 0.002931 5.542 0.090 44.902 0.043 0.022271 0.000021 42.517 0.153 0.185641 0.003021 0.023520 0.000085 8.10 0.13 y 21619 390 -388
DN-6c pre I 1.10503 0.00150 0.186069 0.002074 5.374 0.060 50.637 0.069 0.019748 0.000027 44.685 0.098 0.205611 0.002308 0.022379 0.000049 9.42 0.11 y 22317 276 -276
DN-19-PRE-II 1.03311 0.00165 0.193225 0.003142 5.175 0.084 28.646 0.046 0.034908 0.000056 27.054 0.112 0.199621 0.003262 0.036963 0.000153 5.54 0.09 y 23323 425 -423
DN-47 pre II 1.04122 0.00072 0.194539 0.001827 5.140 0.048 50.544 0.036 0.019785 0.000014 47.725 0.159 0.202558 0.001907 0.020953 0.000070 9.83 0.10 y 23494 246 -246
DN-45 post 1.03315 0.00131 0.198011 0.002015 5.050 0.051 8.291 0.011 0.120612 0.000154 7.841 0.022 0.204574 0.002097 0.127528 0.000358 1.64 0.02 y 23969 273 -273
DN3y(dn4-pre) 1.07078 0.00122 0.201005 0.002673 4.975 0.066 147.405 0.170 0.006784 0.000008 131.900 0.499 0.215231 0.002873 0.007581 0.000029 29.63 0.41 n 24343 364 -362
DN 7 pre 1.06103 0.00116 0.202184 0.001453 4.946 0.036 97.769 0.108 0.010228 0.000011 90.089 0.291 0.214523 0.001559 0.011100 0.000036 19.77 0.15 y 24511 198 -198
DN-2-1 1.07159 0.00258 0.204898 0.006389 4.880 0.152 180.620 0.440 0.005536 0.000013 159.070 0.807 0.219566 0.006867 0.006287 0.000032 37.01 1.17 y 24871 875 -868
DN-48 post 1.07019 0.00201 0.219088 0.001455 4.564 0.030 371.263 0.700 0.002694 0.000005 336.675 0.943 0.234466 0.001618 0.002970 0.000008 81.34 0.56 n 26820 203 -203
DN-48 pre 1.06698 0.00153 0.231348 0.002095 4.322 0.039 199.990 0.289 0.005000 0.000007 182.309 0.759 0.246844 0.002264 0.005485 0.000023 46.27 0.45 n 28534 296 -296
DN-45 pre 1.01720 0.00139 0.235464 0.008070 4.247 0.146 33.501 0.048 0.029850 0.000043 32.429 0.267 0.239513 0.008215 0.030836 0.000254 7.89 0.28 y 29176 1154 -1142
DN-63-post 1.08810 0.00131 0.239780 0.001576 4.170 0.027 338.317 0.492 0.002956 0.000004 208.134 0.539 0.260904 0.001743 0.004805 0.000012 81.12 0.56 n 29701 225 -225
DN-37a-pre 1.07969 0.00213 0.246848 0.001452 4.051 0.024 589.584 1.164 0.001696 0.000003 535.992 1.010 0.266519 0.001653 0.001866 0.000004 145.54 0.84 n 30719 211 -211
DN-21pre-I 1.07807 0.00197 0.258612 0.002636 3.867 0.039 214.996 0.394 0.004651 0.000009 194.417 0.492 0.278803 0.002887 0.005144 0.000013 55.60 0.57 y 32420 387 -386
DN-7-45 1.09876 0.00149 0.264182 0.001660 3.785 0.024 98.217 0.133 0.010182 0.000014 87.533 0.186 0.290272 0.001866 0.011424 0.000024 25.95 0.17 33202 245 -245
DN 6C pre 1.07073 0.00096 0.271344 0.002372 3.685 0.032 655.946 0.588 0.001525 0.000001 599.327 1.082 0.290537 0.002553 0.001669 0.000003 177.99 1.57 34300 352 -352
DN-6c pre II 1.07306 0.00148 0.278515 0.002357 3.590 0.030 305.075 0.427 0.003278 0.000005 277.735 1.090 0.298864 0.002563 0.003601 0.000014 84.97 0.78 n 35363 354 -354
DN7y(dn6C pre) 1.07398 0.00147 0.282250 0.003191 3.543 0.040 518.542 0.710 0.001928 0.000003 471.711 0.984 0.303132 0.003452 0.002120 0.000004 146.36 1.67 35921 483 -481
DN-68b-pre 1.07626 0.00493 0.286271 0.007740 3.493 0.094 152.585 0.189 0.006554 0.000008 112.891 0.697 0.308102 0.008449 0.008858 0.000055 43.68 1.19 36522 1185 -1171
DN-47 post I 1.06773 0.00153 0.290215 0.002591 3.446 0.031 270.852 0.390 0.003692 0.000005 248.270 0.841 0.309871 0.002802 0.004028 0.000014 78.61 0.74 n 37136 398 -396
DN-44 post 1.07758 0.00301 0.298459 0.002847 3.351 0.032 1187.656 3.344 0.000842 0.000002 1069.489 5.248 0.321614 0.003197 0.000935 0.000005 354.47 3.62 n 38375 444 -442
DN-44 pre 1.06962 0.00277 0.299674 0.004578 3.337 0.051 183.547 0.478 0.005448 0.000014 165.790 0.680 0.320537 0.004967 0.006032 0.000025 55.00 0.86 38577 707 -708
DN-63-pre II 1.07924 0.00052 0.303331 0.001827 3.297 0.020 759.525 1.268 0.001317 0.000002 692.217 1.848 0.327367 0.001978 0.001445 0.000004 230.39 1.50 n 39122 283 -283
DN-36 pre III 1.08074 0.00157 0.327807 0.001756 3.051 0.016 60.771 0.089 0.016455 0.000024 55.302 0.144 0.354275 0.001967 0.018083 0.000047 19.92 0.11 y 42965 285 -285
DN-33C1-PRE 1.03957 0.00231 0.328810 0.012842 3.041 0.119 46.600 0.107 0.021459 0.000049 43.433 0.366 0.341821 0.013372 0.023024 0.000194 15.32 0.61 n 43241 2094 -2055
DN-52 post 1.07331 0.00247 0.331142 0.003992 3.020 0.036 168.799 0.390 0.005924 0.000014 153.958 0.499 0.355417 0.004362 0.006495 0.000021 55.90 0.68 n 43519 652 -647
DN-19-PRE-I 1.06999 0.00228 0.369211 0.004406 2.708 0.032 59.591 0.128 0.016781 0.000036 54.258 0.213 0.395054 0.004788 0.018431 0.000072 22.00 0.27 n 49829 762 -756
DN-47 pre I 1.05901 0.00146 0.370490 0.003192 2.699 0.023 54.164 0.075 0.018463 0.000026 49.983 0.143 0.392353 0.003424 0.020007 0.000057 20.07 0.18 y 50089 553 -550
DN-40-pre II 0.92599 0.00159 0.387487 0.033220 2.581 0.221 60.755 0.606 0.016460 0.000164 65.052 5.911 0.358808 0.030767 0.015372 0.001397 23.54 2.94 y 53717 6189 -5841
DN-21 pre II 1.04397 0.00132 0.394516 0.002534 2.535 0.016 51.880 0.066 0.019275 0.000024 48.909 0.134 0.411863 0.002696 0.020446 0.000056 20.47 0.14 y 54345 457 -456
DN 9B pre 1.05794 0.00184 0.400767 0.002665 2.495 0.017 140.492 0.245 0.007118 0.000012 129.828 0.316 0.423986 0.002914 0.007702 0.000019 56.30 0.39 n 55394 488 -486
DN-52 pre 1.07588 0.00156 0.402905 0.002673 2.482 0.016 194.489 0.283 0.005142 0.000007 177.539 0.487 0.433480 0.002943 0.005633 0.000015 78.36 0.55 n 55692 488 -485
DN-51 post I 1.05778 0.00176 0.420808 0.003124 2.376 0.018 53.685 0.089 0.018627 0.000031 49.788 0.102 0.445122 0.003386 0.020085 0.000041 22.59 0.17 n 59048 590 -587
DN-40 pre-II 1.04746 0.00271 0.425050 0.012761 2.353 0.071 63.652 0.165 0.015711 0.000041 59.132 0.075 0.445223 0.013417 0.016911 0.000021 27.06 0.81 n 59897 2429 -2376
DN 6A pre (post) 1.07952 0.00155 0.426233 0.002189 2.346 0.012 716.249 1.033 0.001396 0.000002 652.691 1.153 0.460127 0.002454 0.001532 0.000003 305.29 1.59 n 59936 416 -415
DN-66c-post II 1.18317 0.00280 0.432252 0.005758 2.313 0.031 151.602 0.242 0.006596 0.000011 102.883 0.416 0.511427 0.006919 0.009720 0.000039 65.53 0.90 60527 1080 -1069
DN-14A-PRE-I 1.00241 0.00069 0.448996 0.002596 2.227 0.013 13.949 0.010 0.071692 0.000050 13.707 0.042 0.450078 0.002621 0.072954 0.000224 6.26 0.04 y 64801 517 -516
DN-63-pre I 1.04106 0.00165 0.460476 0.002079 2.172 0.010 25.276 0.037 0.039564 0.000057 18.753 0.045 0.479381 0.002294 0.053326 0.000129 11.64 0.06 y 66781 427 -426
DN-14a-preI 1.00621 0.00065 0.490258 0.004129 2.040 0.017 13.616 0.009 0.073440 0.000048 13.279 0.043 0.493304 0.004167 0.075309 0.000242 6.68 0.06 73220 890 -882
DN-25 post II 1.02651 0.00151 0.523575 0.003173 1.910 0.012 32.303 0.048 0.030957 0.000046 30.954 0.082 0.537453 0.003352 0.032306 0.000085 16.91 0.11 y 80306 738 -733
DN-66c-pre I 1.08715 0.00161 0.577076 0.003083 1.733 0.009 16.608 0.014 0.060213 0.000052 21.702 0.051 0.627366 0.003478 0.046079 0.000109 9.58 0.05 y 92162 790 -785
DN-34a- post 1.04353 0.00278 0.647566 0.003937 1.544 0.009 27.418 0.082 0.036472 0.000109 20.450 0.052 0.675756 0.004485 0.048901 0.000125 17.75 0.10 112216 1264 -1247
DN-51 pre I 1.01478 0.00186 0.702835 0.003010 1.423 0.006 12.580 0.023 0.079494 0.000146 12.234 0.033 0.713225 0.003322 0.081740 0.000223 8.84 0.04 y 131346 1171 -1158
DN-33c2-post 1.05619 0.00251 0.715824 0.004742 1.397 0.009 58.259 0.139 0.017165 0.000041 54.230 0.126 0.756049 0.005321 0.018440 0.000043 41.70 0.27 134388 1848 -1814
DN-46 pre I 1.03657 0.00146 0.718347 0.002542 1.392 0.005 32.004 0.045 0.031246 0.000044 30.531 0.089 0.744620 0.002834 0.032753 0.000095 22.99 0.10 y 136133 1017 -1008
DN-25 post I 0.97948 0.00241 0.712367 0.034429 1.404 0.068 15.482 0.062 0.064593 0.000258 15.671 0.614 0.697751 0.033766 0.063813 0.002499 11.03 0.69 136503 14315 -12605
DN-66b-pre 1.00470 0.00290 0.723686 0.030466 1.382 0.058 12.542 0.034 0.079733 0.000217 8.068 0.166 0.727084 0.030681 0.123950 0.002547 9.08 0.42 y 139648 12826 -11444
DN-34a-pre II 1.06637 0.00318 0.747255 0.005142 1.338 0.009 145.286 0.325 0.006883 0.000015 210.379 0.696 0.796849 0.005976 0.004753 0.000016 108.57 0.76 n 146004 2253 -2203
DN-36 post-II 0.98185 0.00116 0.736410 0.004835 1.358 0.009 10.269 0.025 0.097382 0.000235 8.454 0.025 0.723042 0.004824 0.118289 0.000354 7.56 0.05 y 146262 1858 -2302
DN-33c2-pre 1.05609 0.00222 0.747350 0.003801 1.338 0.007 65.206 0.137 0.015336 0.000032 60.751 0.121 0.789269 0.004342 0.016461 0.000033 48.73 0.24 146544 1674 -1644
DN-46 pre II 1.05637 0.00186 0.753394 0.005982 1.327 0.011 123.125 0.217 0.008122 0.000014 115.016 0.303 0.795864 0.006472 0.008694 0.000023 92.76 0.75 y 149020 2619 -2556
DN-36 pre II 1.04813 0.00213 0.765092 0.003911 1.307 0.007 62.241 0.113 0.016067 0.000029 83.208 0.275 0.801916 0.004411 0.012018 0.000040 47.62 0.27 154473 1861 -1824
DN-34a-pre I 1.02974 0.00248 0.772466 0.004266 1.295 0.007 23.443 0.057 0.042656 0.000103 22.490 0.061 0.795439 0.004792 0.044464 0.000120 18.11 0.10 y 158935 2155 -2108
DN-22-POST-II 1.06510 0.00245 0.787660 0.004897 1.270 0.008 113.174 0.261 0.008836 0.000020 104.703 0.276 0.838935 0.005561 0.009551 0.000025 89.14 0.56 n 163707 2507 -2446
DN-46 post 0.95424 0.00121 0.790934 0.004829 1.264 0.008 8.945 0.011 0.111798 0.000142 9.254 0.029 0.754743 0.004706 0.108059 0.000344 7.07 0.05 y 174544 2862 -2784
DN-37a post 0.94086 0.00138 0.796245 0.003630 1.256 0.006 9.923 0.015 0.100776 0.000148 5.400 0.018 0.749155 0.003587 0.185180 0.000610 7.90 0.04 y 178984 2362 -1790
DN-27-II 0.99633 0.00134 0.851074 0.003439 1.175 0.005 20.347 0.027 0.049147 0.000066 20.150 0.033 0.847954 0.003612 0.049629 0.000082 17.32 0.07 207662 2776 -2702
DN-62 post II 1.04862 0.00208 0.861741 0.007262 1.160 0.010 29.170 0.058 0.034281 0.000068 27.371 0.111 0.903637 0.007822 0.036535 0.000148 25.14 0.23 y 207847 5571 -5291
DN-40-pre I 1.00703 0.00138 0.892474 0.003645 1.120 0.005 25.951 0.036 0.038534 0.000053 25.407 0.069 0.898748 0.003872 0.039360 0.000107 23.16 0.11 y 240828 4005 -3857
DN-26top-postI 1.01528 0.00082 0.903439 0.003346 1.107 0.004 13.869 0.011 0.072104 0.000058 13.466 0.023 0.917245 0.003477 0.074261 0.000126 12.53 0.05 250043 3850 -3717
DN-62 post I 1.04910 0.00090 0.914560 0.010862 1.093 0.013 14.828 0.014 0.067440 0.000062 14.005 0.108 0.959462 0.011425 0.071402 0.000550 13.56 0.19 y 253340 12464 -11197
DN-36 post I 1.03745 0.00347 0.912117 0.005580 1.096 0.007 28.164 0.075 0.035506 0.000095 34.060 0.088 0.946279 0.006597 0.029360 0.000076 25.69 0.14 253643 7157 -6679
DN-40 post I (2) 0.95030 0.00114 0.919318 0.005239 1.088 0.006 14.824 0.018 0.067457 0.000082 15.419 0.050 0.873626 0.005088 0.064856 0.000211 13.63 0.09 296208 9310 -9456
DN-65 post 1.05926 0.00101 0.954019 0.005656 1.048 0.006 237.027 0.230 0.004219 0.000004 221.659 0.937 1.010557 0.006068 0.004511 0.000019 226.13 1.63 n 301492 10009 -9185
DN-42e-pre 1.07104 0.00118 0.962967 0.004903 1.038 0.005 18.805 0.021 0.053176 0.000059 17.345 0.044 1.031375 0.005373 0.057652 0.000147 18.11 0.10 n 311281 9461 -8720
DN-66c-pre II 1.03939 0.00090 0.959147 0.008001 1.043 0.009 34.015 0.054 0.029399 0.000047 15.016 0.042 0.996932 0.008361 0.066596 0.000188 32.63 0.28 y 320296 17481 -15087
DN-36 pre I 1.02635 0.00142 0.957855 0.002932 1.044 0.003 34.036 0.061 0.029380 0.000053 15.456 0.036 0.983097 0.003302 0.064699 0.000149 32.60 0.11 y 325384 7240 -6771
DN34a-pre III 1.02381 0.00184 0.960071 0.005248 1.042 0.006 23.128 0.048 0.043238 0.000089 22.022 0.094 0.982925 0.005657 0.045409 0.000193 22.20 0.15 y 331793 13731 -12152
DN-65 pre 1.04065 0.00140 0.969092 0.007858 1.032 0.008 579.889 0.786 0.001724 0.000002 552.497 1.983 1.008484 0.008289 0.001810 0.000006 561.97 4.90 n 340805 21364 -17886
DN-22-POST-I 0.94199 0.00197 0.951661 0.003770 1.051 0.004 5.835 0.012 0.171365 0.000358 6.125 0.012 0.896456 0.004013 0.163262 0.000313 5.55 0.02 y 394924 24176 -19364
DN-22-PRE-II 1.02405 0.00208 0.982110 0.004502 1.018 0.005 13.778 0.028 0.072579 0.000148 13.298 0.034 1.005731 0.005044 0.075199 0.000194 13.53 0.07 y 395927 22847 -18817
DN-40-post I 0.91731 0.00264 0.976004 0.003881 1.025 0.004 12.927 0.037 0.077355 0.000223 13.942 0.041 0.895297 0.004397 0.071726 0.000213 12.62 0.04 y 873592 -11608 19656
DN-26top-preI 1.00029 0.00102 1.057427 0.001780 0.946 0.002 9.798 0.010 0.102060 0.000104 9.712 0.017 1.057729 0.002082 0.102962 0.000177 10.36 0.02 y eq. 150 -150
DN-62 pre I 1.01571 0.00056 1.017429 0.004056 0.983 0.004 12.237 0.007 0.081722 0.000045 11.944 0.037 1.033415 0.004159 0.083724 0.000260 12.45 0.06 y eq.
DN-22-PRE-I 0.98376 0.00180 0.994981 0.003357 1.005 0.003 10.613 0.020 0.094224 0.000173 10.671 0.029 0.978819 0.003758 0.093713 0.000251 10.56 0.04 y eq. 2658 -2590
Table 2: Isotopic ac<strong>tivity</strong> ratios of seismite samples as calculated from MC-ICP-MS isotopic measurements, arranged by age for Isochron calculations.
Pre-seismic event samples are marked in red. Post-seismic samples are marked in black.
The detrital component of samples was established in the lab for most samples. Markings in blue are for samples that were established in the lab ex post facto as near as possible to the original sample.

,10.4±0.7
שהשאירו את חותמן בספלאותמים במערת דניה ‏(מספרים באלפי שנים)‏ :
,4.8±0.8
.160±45 ,147.6±5.4 ,137±29 ,57.9±5.2 ,38.0±2.7 ,29.1±3.3 ,20.8±3.0
השוואה של ממצאים אלה עם גילי אירועים סייסמיים שדווחו במחקרים פלאוסייסמים אחרים שנערכו
בישראל הראתה שלכל תשעת האירועים ניתן למצוא תיארוך מקביל במחקר אחר.‏ השוואה זו מאששת
את ההנחה שגילי השבירה של ספלאותמים ממערת דניה אינם אקראיים ושהדוגמאות שנבדקו אכן נשברו
כתוצאה מאירועים סייסמיים.‏ חלק מהגילים שנמצאו לסייסמיטים מהמערה מראים התאמה לגילים שדווחו
לארועים סייסמיים שפקדו את בקע ים המלח,‏ כמו גם לגילים שדווחו לארועים בהעתק הכרמל.‏ דרושים
מחקרים נוספים בכדי לבחון את המקור לרעידות האדמה המדווחות במחקר זה.‏
90

תקציר
הר הכרמל מוגדר מצידו המזרחי על ידי העתק הכרמל,‏ שכיוונו הכללי צפ'-מע'.‏ העתק זה הוא שלוחה של
מערכת ההעתקה בבקע ים המלח.‏ מערת דניה נמצאת בשכונת דניה בעיר חיפה,‏ על שיפולי שלוחה
היורדת מערבה לכיוון טירת הכרמל.‏ זוהי מערה קארסטית שבה נראים משקעי מערות ‏(ספלאותמים)‏
שבורים,‏ מפולות סלעים וסדקים,‏ העשויים להוות עדויות לכך שהנזקים האלה נגרמו כתוצאה מרעידות
אדמה.‏ מטרות המחקר הזה הן לבדוק האם הספלאותמים השבורים במערת דניה הם סמנים לפעילות
סייסמית ‏(סייסמיטים),‏ שמהם ניתן ללמוד על ההיסטוריה של רעידות האדמה שפקדו את האזור ברביעון.‏
ראשית מופתה המערה עם כל תופעות השבירה והמעוות בתוכה,‏ תוך כדי שלילה של גורמים אחרים
שאינם קשורים לרעידות אדמה שיכלו לגרום להיווצרות התופעות האלה.‏ מקומות שבהם זוהתה אי
התאמה בשכוב של למינות במשקעי המערה מזוהים כאזורים של ‏'מגע סייסמי'‏ והלמינות הכי קרובות
לאותו מגע נדגמו למטרות תיארוך.‏ גילה של הלמינה האחרונה שהושקעה לפני אי ההתאמה ו/או הלמינה
הראשונה ששקעה אחרי אי ההתאמה,‏ מהווה אילוץ לגיל האירוע שיצר את אי ההתאמה.‏ הסייסמיטים
השונים סווגו לפי סוג הספלאותם,‏ מידת הבהירות של המגע הסייסמי כסמן לארוע סייסמי והמידה בה
ניתן היה לדגום את הלמינות הרצויות.‏ סיווג זה תרם לבחינה של מידת האמינות של הממצאים.‏
הלמינות הנדגמות תוארכו בשיטת התיארוך של מערכת הדעיכה של אורניום
לתוריום (U)
.(Th)
משוואות הגיל של שיטה זו מבוססות על כך שהמערכת נקיה מתוריום שמקורו דטריטי ושעשוי להשפיע
על תוצאות הגיל.‏ כאשר נמצא חומר דטריטי בספלאותמים יש צורך בתיקון לגילים המתקבלים.‏ התיקון
לתוריום דטריטי לגילי הדוגמאות ממערת דניה נעשה בשיטה של איזוכרון.‏ על פי קריטריונים שמבוססים
על כמות החומר הדטריטי בדוגמה והמאפיינים של הלמינה מהן נלקחה הדוגמה,‏ הדוגמאות השונות חולקו
לקבוצות שוות גיל ובעזרת דיאגרמת איזוכרון נקבע גיל משותף לכולן.‏
68 דוגמאות ספלאותמים נאספו לבדיקה ממערת דניה.‏ 37 מתוכן הן דוגמאות של סייסמיטים ומתוכן,‏
32
נבדקו לשם תיארוך.‏ מתוך הדוגמאות שתוארכו עשרה סייסמיטים הם זקיפים קטומים שנשברו לאורך
מישורים כמעט אופקיים.‏ תשעה סייסמיטים הם נטיפים קטומים בצורות ואורכים שונים ושאר הדגימות
נלקחו מגלעינים של משקעי זרימה קלציטיים מרצפת המערה שבהם נמצאו אי התאמות בשיכוב וחלקם
שקעו מעל שברי ספלאותמים קדומים יותר.‏
הגילים שחושבו ע"י איזוכרונים של קבוצות הסייסמיטים השונות מהווים את הגיל המוערך של הארוע
הסייסמי שיצר אותם.‏ לאורך
200
אלף השנים האחרונות,‏ נמצאו תשעה ארועים של רעידות אדמה
89

משרד התשתיות הלאומיות
המכון הגיאולוגי
תיארוך אירועים סייסמים קדומים על העתק הכרמל
באמצעות ספלאותמים שבורים ממערת דניה בכרמל
יעל בראון
עבודת זו הוגשה כחיבור לקבלת תואר ‏"מוסמך במדעי הטבע"‏ במכון למדעי כדור הארץ,‏
האוניברסיטה העברית,‏ ירושלים.‏
העבודה נעשתה בהדרכתם של:‏
פרופ'‏ אמוץ עגנון,‏ המכון למדעי כדור הארץ,‏ האוניברסיטה העברית,‏ ירושלים
דר ‏'מירה בר-מטיוס,‏ המכון הגיאולוגי,‏ ירושלים
דוח מס'‏ GSI/23/2010
ירושלים,‏ חשון,‏ תשע"א