Archaeoseismology and Palaeoseismology in the Alpine ... - Tierra

elt. The degrading metamorphic basement shows strong
new activity, which makes this area one of the main
earthquake activity zones in East China. According to the
historic record, earthquakes of 5.0 magnitude or greater
have hit this area for nine times, among which there are
two earthquakes of more than 6.0 magnitude. The
epicentre presents belt distribution from north to east.
The digging site is in the eastnorth of the earthquake
zone. Sand veins were discovered in the cultural stratum
(Fig. 1).
Fig. 2: The tensile fault in Longshan Cultural Stratum in the
ancient site in North Anhui Province (The up photo is the
north wall; the down photo is the south wall)
In the above figure (Fig. 1), the grey stratum which, the
sand penetrated in is the cultural stratum of Western
Zhou Dynasty (about 2,000 years ago). The sand vein
originated from a sand stratum 6 meter below the
ground. Earthquake liquefaction can account for the
origin of the sand vein.
1 st INQUA‐IGCP‐567 International Workshop on Earthquake Archaeology and Palaeoseismology
24
Fault and crack in Longshan cultural stratum of the
ancient site in North Anhui Province
This ancient site formed in the Longshan Period. There are
tensile faults in the city wall. The strike is 10°, SEE. The dip
is nearly vertical. Tensile dislocation is discovered in ash
layers and construction heaps. Fault displacement in
different layers is about the same, ranging from 3.8
centimeter to 4.5 centimeter. The fracture section is flat,
except for the dragging with same direction in the upper
surface of the cultural stratum and the fault is displayed
in the north wall, south wall and the bottom of the trench
(Fig. 2). In the corresponding cultural stratum on the east
side, an about 20‐centimeter‐broad crack is discovered,
the direction of which is EN 20°. The crack is filled with
black soil. We can see this clearly from the two sides and
the bottom of the trench. The fault and crack developed
in the same cultural stratum. Both of them seem to be the
results of tensile deformation. The fact that they occur in
the cultural stratum made of comparatively plastic clay
soil and end in the bottom of the upper stratum revealed
that they are the relics of quick fracture. Their occurrence
can be attributed to earthquake deformation (Yao
Daquan, 2004). According to the assembly of fragments of
cultural relics, the cultural stratum is Longshan cultural
stratum, which has about 4,300 years’ history.
Joints discovered in the ancient site in central Anhui
Province
Joints are mainly discovered in the prehistoric sites, which
have history of about 5,500 years. During the excavation
process, generally the joint surfaces are gently inclined
and clearly cut through the layers. The cutting crack can
be observed in some part of the joints.
DEFORMATION OF BURIAL CHAMBERS
The Fig. 3 is the digging scene of Warring States Period
tomb in central Anhui Province: There the bulge
deformation is obviously on the bottom of the chamber,
which is the characteristic of deformation under
compressive stress.
SUBSIDENCE OF THE RELICS
The ancient pathway excavated in a site in North Anhui
province is one meter underneath the ground, which is
the indicator of a continuous subsiding process. Furrows
can be discerned in the silt underneath the north river
channel. The furrows are buried by a 1.5‐meter‐high layer
made of rubbles and new deposits. A complex subside‐
rise‐subside process can be perceived from the Fig. 3.
CONCLUSIONS
Based on the above presentation and preliminary
analysis, it can be concluded that the archaeological work
in ancient sites in Anhui Province has disclosed the
natural deformation traces in this area. Cases of natural
deformation have happened in Jianghuai area, which
locates in the transition belt between North China and
South China since Neolithic Age. Among these cases there
must be earthquakes. However, we only have the record
of earthquakes with more than 5.0 magnitude in this area
in the last 500 years. (Huang Weiqiong et al., 1994).
Evidently, the above materials play an important role in