HR: 1330h
AN: T12C-0486    [PDF]
TI: A New Look for the Cause of the 1906 Meishan Earthquake in Southwestern Taiwan From Shallow Seismic Reflection Images
AU: * Shih, R
EM: seirock@eq.ccu.edu.tw
AF: National ChungCheng University, 160 SanHsing, MinHsiung, Chiayi, 621 Taiwan
AU: Chen, W
EM: wenshan@ms.cc.ntu.edu.tw
AF: National Taiwan University, P.O. Box 13-318, Taipei, 106 Taiwan
AU: Lin, C
EM: lincw@linx.moeacgs.org.tw
AF: Central Geological Survey, 2, Ln. 109, HuaHsin St., ChunHo, Taipei, 235 Taiwan
AB: In 1906, an earthquake of magnitude 7.1 shocked the Meishan area in the southwestern Taiwan, and caused very severe damages. Formerly, the earthquake was thought related to a NE-SW trend, left-lateral strike-slip fault, called Meishan fault. Since the Meishan fault runs in the plain area, without visible outcrops, the followed up study of the fault was difficult. Using the high resolution shallow seismic reflection data, in this paper, we will show not only the Meishan fault, but a N-S trend thrust fault, named Chiochiunken fault, in the foothill front area also played a more important role in that earthquake. From the shallow seismic reflection images, we have been able to detect the detailed locations for both of the faults and show their characteristics in near surface. The two faults were connected probably in the northeast of the Meishan area. The Chiochiunken fault consists of a sharp and narrowed fault zone in the Meishan area and dipping to the east at about 25 degree. Down to the south in the Chuchi area, the fault zone was widely spread to about 800m, and many smaller faults exist within the zone. The Meishan strike-slip fault consists of a clear wide fault zone along the fault trace. The flower structures were also clearly imaged in the shallow seismic reflection sections. According to the relation of the two faults and the known tectonic movement of Taiwan, we believed that the 1906 Meishan earthquake was first occurred along the Chiochiunken fault and then the Meishan fault was triggered as well.
DE: 3025 Marine seismics (0935)
DE: 7223 Seismic hazard assessment and prediction
DE: 8010 Fractures and faults
SC: Tectonophysics [T]
MN: 2003 Fall Meeting