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Archaeoseismology and Palaeoseismology in the Alpine ... - Tierra

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statue was estimated around late 8 th century. Its weight is<br />

about 70 tons <strong>and</strong> its dimension is about 250×190×620<br />

cm. Accidentally, <strong>the</strong> tim<strong>in</strong>g of <strong>the</strong> earthquake <strong>in</strong> 779 AD<br />

is co<strong>in</strong>cide with <strong>the</strong> carv<strong>in</strong>g age of <strong>the</strong> Buddha statue.<br />

Therefore, <strong>the</strong> possibility of <strong>the</strong> <strong>in</strong>terrelationship between<br />

<strong>the</strong> fall<strong>in</strong>g of <strong>the</strong> Buddha statue <strong>and</strong> <strong>the</strong> 779 AD<br />

earthquake was exam<strong>in</strong>ed, <strong>and</strong> its orig<strong>in</strong>al location <strong>and</strong><br />

direction were restored.<br />

Fig. 2: a) & b) Overview of <strong>the</strong> study site show<strong>in</strong>g unstable slope<br />

<strong>and</strong> <strong>the</strong> fallen Yeolam Buddha statue. c) close‐up photograph of<br />

<strong>the</strong> face of <strong>the</strong> Yeolam Buddha statue (from J<strong>in</strong> et al., <strong>in</strong> press).<br />

To trace <strong>the</strong> orig<strong>in</strong>al position of <strong>the</strong> fallen Buddha statue,<br />

we performed <strong>the</strong> fracture analysis on <strong>the</strong> fallen Buddha<br />

1 st INQUA‐IGCP‐567 International Workshop on Earthquake Archaeology <strong>and</strong> <strong>Palaeoseismology</strong><br />

64<br />

statue <strong>and</strong> <strong>in</strong> situ granite. A well exposed outcrop was<br />

selected to analyze <strong>the</strong> structural elements such as faults,<br />

jo<strong>in</strong>ts, <strong>and</strong> ve<strong>in</strong>s. A 1m × 1m grids were made for this<br />

fracture mapp<strong>in</strong>g (Fig. 3). We also measured o<strong>the</strong>r<br />

fractures <strong>in</strong> situ granites <strong>and</strong> envelop<strong>in</strong>g planes of <strong>the</strong><br />

Buddha statue.<br />

Four ma<strong>in</strong> fracture sets were identified <strong>in</strong> <strong>the</strong> <strong>in</strong> situ<br />

granite. The attitudes of <strong>the</strong> fracture sets are recognized<br />

as follows: EW/65°N (set A), N12°E/79°SE (set B),<br />

N63°W/55NE (set C), NS/82°W (set D), <strong>and</strong> N13°W/8°SW<br />

(set E; sheet<strong>in</strong>g jo<strong>in</strong>ts) (Fig. 3, 4). The fracture sets were<br />

named from set A to set E, arbitrarily. The fallen Buddha<br />

statue is enveloped by six planes. The attitudes of <strong>the</strong> five<br />

planes are as follows: N36°W/60°NE (bottom plane),<br />

N24°E/36°NW (back side), N77°W/58°SW (south side)<br />

EW/68°N (north side) (Fig. 4). We could not measure <strong>the</strong><br />

carv<strong>in</strong>g plane, because of <strong>the</strong> protection plan of <strong>the</strong><br />

cultural properties.<br />

The fractures measured around <strong>the</strong> fallen Buddha statue<br />

are compared with <strong>the</strong> fracture sets determ<strong>in</strong>ed from <strong>the</strong><br />

<strong>in</strong> situ granite. The fractures measured off <strong>the</strong> fallen<br />

Buddha statue well matched with <strong>the</strong> fracture sets from<br />

<strong>in</strong> situ granite if <strong>the</strong> fallen statue were rotated 20°<br />

clockwise back to its orig<strong>in</strong>al position. Therefore, it is<br />

<strong>in</strong>terpreted that <strong>the</strong> Buddha statue fell down with 20°<br />

anticlockwise rotation (Fig. 4).<br />

Fig. 3: Detailed grid map on <strong>the</strong> horizontal plane around <strong>the</strong> fallen Yeolam Buddha statue. a) Photo mosaic of <strong>the</strong> horizontal plane. b) Sketch<br />

map of <strong>the</strong> structural elements <strong>and</strong> locations of sense <strong>in</strong>dicators of <strong>the</strong> horizontal section. Note that <strong>the</strong> equal‐area stereographic projection<br />

shows fracture sets developed <strong>in</strong> horizontal plane. b‐1 & b‐2: Slip sense <strong>in</strong>dicators on <strong>the</strong> horizontal plane show left‐lateral slip set C cross‐<br />

cutt<strong>in</strong>g set B (from J<strong>in</strong> et al., <strong>in</strong> press).

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