Archaeoseismology and Palaeoseismology in the Alpine ... - Tierra

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subsidence of the floor of about 50 cm with lateral dragging can be observed and furthermore a concrete reconstruction of the subsided floor during Carolingian times. Up to now this is the only part of the Cathedral where two ground floors of Carolingian age can be found (Fig. 5). During the still lasting excavation further cracks have been found in the wall of the octagon. Cracks are systematically (Fig. 6) with a maximum oriented NW‐SW according to the present‐day principal stresses in Central Europe (Reicherter et al., 2008). Large cracks have also been found in the roof of the chapel (Fig. 7). These cracks are lead‐filled and sealed with Carolingian mortar. This evidence also suggests an intra‐Carolingian phase of repair. Archaeological investigations imply that obviously the chapel was architectonically not finished, when the damage occurred. Most probably the damage happened before the official inauguration. Equal Area Fig. 5: Ground floor damage and repair N = 13 Circle = 31 % Fig. 6: Orientation of the wall cracks Geological evidence In the WNW section, the loessy and loamy sediments show angular cracks and fragments (Fig. 8 and 9), which are not related to permafrost features but are interpreted as liquefaction. Furthermore, some of the cracks are filled with black sterile clay from below as they open downwards. These structures may be interpreted as “injection structures” or features of weathered Devonian claystones into the overlying Pleistocene. However, some of the upper portions of the cracks yield Roman ceramic fragments and charcoal, quite similar to 1 st INQUA‐IGCP‐567 International Workshop on Earthquake Archaeology and Palaeoseismology) 134 Fig. 7: Damage in the roof of the chapel those sediments found in adjacent Roman waste dumps, pointing to a mixture of underlying and covering materials. Liquefaction and injections structures occur usually during earthquake with a magnitude higher than 5.5, which is corroborated by large cracks in the massive outer walls. Fig. 8: Clay‐filled cracks in the sterile soil of the chapel (Pleistocene Loess) HISTORICAL EARTHQUAKES AND DATING The earthquake catalogues (e.g., von Hoff, 1840) and the Annales regni Francorum (Kurze, 1895) provide two important passages for historical earthquakes in the region of Aachen. Both fall into a relatively short time interval. One in winter 803 AD: “Hoc hieme circa ipsum palatium et finitimas regiones terrae motus factus et mortalitas subsecuta est.“ The later 829 AD (between Ash Wednesday and Easter) description „Aquisgrani terrae motus noctu factus ventusque tam vehemens coortus ut non solum humiliores domos, verum etiam ipsam sanctae Dei genitricis basilicam, quam capellam vocant, tegulis plumbeis tectam non modica denudaret parte“. Both notes tell of earthquake shaking and significant structural damage (e.g. lead bricks fallen off the roof) and fatalities. Due to rich findings and dating of charcoal in several levels, the original and the restored floor, successful radiometric dating was carried out to get time constraints
on the exact date of the earthquake event. This was also important to get a time frame of the construction of the chapel. So, construction started earliest in 798 AD, supported by findings of a Carolus denar of a maximum age of 794 AD during the excavations. The construction was terminated latest in 813 AD. Fig. 9: Detail of the sharp‐edged clay‐filled cracks in the Pleistocene Loess, suggesting a high‐energy event CONCLUSIONS Several typical indicators of earthquake deformation (structural and geological) have been found in the Carolingian Chapel of Aachen, which indicate a high‐ energy event, probably accustomed by differential ground settling. Historical documents reveal evidence for two earthquakes in the considered time interval. Palaeoseismic trenching investigations of Vanneste et al. (2001) found surface rupturing during an earthquake near Bree (Belgium), which happened around 800 AD and assigned a palaeomagnitude of M 6.4 to this earthquake (see also summary in Camelbeeck et al., 2007). Also, the structural damage in Cologne (Hinzen and Schütte, 2002) occurred around 800 to 840 AD. These authors end up with a minimum magnitude of 5.8. If we take into account that structural damage in the Aachen Cathedral occurred during the construction, as evidenced by the warped ground floor (see Fig. 5), we favour strongly the 803 AD event as the candidate earthquake for the damage in the medieval Aachen city 1 st INQUA‐IGCP‐567 International Workshop on Earthquake Archaeology and Palaeoseismology) 135 area. The observed damage, including the liquefied “injection structures” suggest a minimum magnitude for this event around 5.5. However, up to date trenching studies to localize the causative fault in the Aachen area is missing. Currently, we are mapping and surveying faults in the area. Acknowledgements: We thank Helmut Maintz, the Master builder (Dombaumeister, Cathedral Architect) of the Aachen Cathedral, for support and access. References Camelbeeck, T., and Meghraoui, M. (1998). Geological and geophysical evidence for large paleoearthquakes with surface faulting in the Roer Graben (northwest Europe), Geophys. J. Int., 132, 347 ‐ 362. Camelbeeck, T., Vanneste, K., Alexandre, P., Verbeeck, K., Petermans, T., Rosset, P., Everaerts, M., Warnant, R. and Van Camp, M. (2007). Relevance of active faulting and seismicity studies to assessments of long‐term earthquake activity and maximum magnitude in intraplate northwest Europe, between the Lower Rhine Embayment and the North Sea. GSA, Spec. Paper, 425, 193‐224. Hinzen, K.‐G. and Schütte, S. (2002). Evidence for earthquake damage on Roman buildings in Cologne, Germany. Seismological Research Letters, 74, 121‐137. Hinzen, K.‐G. and Reamer, S.K. (2007). Seismicity, seismotectonics, and seismic hazard in the northern Rhine area. GSA, Spec. Paper, 425, 225‐242. Kurze, F., (1895). Annales regni Francorum iude ab a. 741 ad a. 829, qui dicuntur Annales Laurissenses maiores et Einhardi (Hannover). Skupin, K., Buschhüter, K., Hopp, H., Lehmann, K., Pelzing, R., Prüfert, J., Salamon. M., Schollmayer, G., Techner, A. and Wrede, V., (2008). Paläoseismische Untersuchungen im Bereich der Neiderrheinischen Bucht. Scriptum, 17, 5‐72 (in German). Reicherter, K., Froitzheim, N., Jarosiński, M., Badura, J., Franzke, H.‐J., Hansen, M., Hübscher, C., Müller, R., Poprawa, P., Reinecker, J., Stackebrandt, W., Voigt, T., von Eynatten, H. and Zuchiewicz, W., 2008. Alpine Tectonics II – Central Europe north of the Alps (Geology of Central Europe; McCann, T. (ed) book section). Spec. Publ. Geol. Soc. London, 59 pp. Von Hoff, K.E.A., (1840). Chronik der Erdbeben und Vulcan‐ Ausbrüche, I. Theil (Justus Perthes, Gotha), pp. 470. Vanneste, K., Verbeeck, K., Camelbeeck, T., Paulissen. E., Meghraoui, M., Renardy, F., Jongmanns, D. and Frechen.M. (2001). Surface‐rupturing history of the Bree fault scarp, Roer Valley Grabe: Evidence for six events since the late Pleistocene. J. of Seismology, 5, 329‐359.
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Abstracts Volume Archaeoseismology
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Edita e imprime: Sección de Public
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1 st INQUA‐IGCP‐567 Internation
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the importance of performing absolu
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indicative of strike‐slip faultin
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DISCUSSION Based on detailed field
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Table 1: Source parameters used in
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elations. However, the attenuation
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mostly concentrated on the DST in I
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continuous support. N. Shalev, G. G
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The tumulus initial morphology show
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our understanding and prediction of
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spans, with a threefold increase fr
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Nevertheless the lack of research,
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earthquake. In uncertain cases, as
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The site reconnaissance successfull
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Table 1: Surface faulting extent re
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The graben has a markedly asymmetri
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are a valuable addition to the rout
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to 400 m) the calculated values for
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RISK ANALYSIS The created hazard ma
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290 m water depth the basin accumul
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CONCLUSIONS From the palaeostress a
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Fig. 2: Geological map of the study
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however, the massive 1995 earthquak
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mapped on the slopes above Qiryat
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interpreted as either an expression
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The Shepran Cave is located on the
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Page 85 and 86: 1 st INQUA‐IGCP‐567 Internation
Page 87 and 88: properties. The mean value of speci
Page 91 and 92: excavated a deep trench, thus provi
Page 99 and 100: Fig. 8: Seismic ground shaking may
Page 101 and 102: elevant qualitative criteria are po
Page 103 and 104: CONCLUDING REMARKS The exposed exam
Page 105 and 106: produced by significantly different
Page 107 and 108: It is possible that a portion of th
Page 109 and 110: In addition, the Database of histor
Page 111 and 112: were published by IGME (1983) and E
Page 115 and 116: The city collapsed and it was aband
Page 119 and 120: Fig. 4: Slipped lintel in a window
Page 121 and 122: to overcome shear resistance and in
Page 123 and 124: Newmark, N.M. (1965). Effects of ea
Page 125 and 126: associated with various tsunamis (<
Page 129 and 130: this method, the magnitude of the e
Page 133 and 134: etween pieces. Fragments have not f
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Page 139 and 140: THE ARCHAEOLOGICAL ZONE COLOGNE Aft
Page 143 and 144: affecting the Alcázar was about 50
Page 147 and 148: archaeoseismology could instead bec
Page 149 and 150: In the area later occupied by Vilni
Page 155 and 156: Fig. 2: Assemblage of landforms ass
Page 157 and 158: Fig. 8: Data and regression for mag
Page 159 and 160: Fig. 3: Relationships among magnitu
Page 161 and 162: CONCLUSIONS 1. Spatial distribution
Page 163 and 164: The stratigraphic sequence (Fig. 4)
Page 165 and 166: especially in the zones of hanging
Page 169 and 170: interpretations are based on relati
Page 173 and 174: Fig. 5: Gray‐scale value laser im
Page 177 and 178: (~40 cm), F‐ rotated building str
Page 179 and 180: Index 1 st INQUA‐IGCP‐567 Inter
Page 181: 1 st INQUA‐IGCP‐567 Internation
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