Archaeoseismology and Palaeoseismology in the Alpine ... - Tierra

DISCUSSION
The falling time of the Buddha statue is important to
analyse earthquake hazards for a specific earthquake.
From the artistic style and weathering condition of the
Buddha statue, the falling time could be estimated
roughly. However, we can not determine the exact falling
time from these methods. Recently, optically stimulated
luminescence (OSL) dating method has emerged as a
powerful dating method for these cases, because quartz
and feldspar to be dated are abundant in this situation
(Choi et al, 2009). The fallen Buddha statue is lying on the
weathering soil of Cretaceous granite. If we can collect
suitable materials for OSL dating, the falling time could be
determined. It could indicate the interrelationship
between the falling Buddha statue and 779 AD
earthquake. Therefore, further studies are required to
solve this problem.
Many Quaternary faults were reported around the study
area. The aerial photograph of the area shows obviously
NE‐SW, NNE‐SSW, and E‐W trending lineaments. Data
obtained from trenches excavated across active faults are
of great value in studies of earthquake hazards.
Therefore, if we find Quaternary faults around the
Buddha statue, they could provide useful information for
paleo‐earthquakes in this area.
CONCLUSIONS
The study area is located around the junction between
the Yangsan and Ulsan faults. Recently many Quaternary
faults have been reported along the Yangsan and Ulsan
faults encouraging researches on the fault activities and
associated paleoseismicities. According to historical
records, the study area was significantly affected by
earthquakes. The earthquakes produced heavy casualties
and damages in historical properties. Although we need
additional absolute dating data, the falling time of the
Buddha looks coincident with the 779 AD earthquake,
which killed over one hundred people. Fracture sets
measured from the fallen Buddha statue well match with
those fractures measured from nearby in situ granite if
the fallen statue were rotated 20° clockwise back into
their original positions. It indicates that the Buddha statue
might be fallen down with 20° counterclockwise rotation.
Although we can not sure about the consistency of the
timing between the falling time of the Buddha statue and
the 779 AD earthquake, it must be fallen down by any
episodic force such as landslides or earthquakes. This idea
1 st INQUA‐IGCP‐567 International Workshop on Earthquake Archaeology and Palaeoseismology
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is supported by the weathering condition of the Buddha
statue, the distribution of surrounding blocks, and the
geomorphological pattern of the slope around the statue.
Other earthquake damages were also reported in
historical records. Based on recent geological and
archaeoseismological studies, the Gyeongju area might
not be free from future earthquake hazards.
Acknowledgements: This work was funded by the Korea
Meteorological Administration Research and Development
Program under Grant CATER 2008‐5502.
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