HR: 1330h
AN: T12C-0483    [PDF]
TI: Paleoseismology of the Chelungpu Fault During the Past 1900 Years
AU: * Chen, W
EM: wenshan@ccms.ntu.edu.tw
AF: Department of Geosciences, National Taiwan University, No. 1, Roosevelt Rd., Sec. 4, Taipei, 106 Taiwan
AU: Lee, K
EM: oldr123@yahoo.com.tw
AF: Department of Geosciences, National Taiwan University, No. 1, Roosevelt Rd., Sec. 4, Taipei, 106 Taiwan
AU: Lee, L
EM: contractor@pchome.com.tw
AF: Department of Geosciences, National Taiwan University, No. 1, Roosevelt Rd., Sec. 4, Taipei, 106 Taiwan
AU: Yang, C B
EM: d91224003@ntu.edu.tw
AF: Department of Geosciences, National Taiwan University, No. 1, Roosevelt Rd., Sec. 4, Taipei, 106 Taiwan
AU: Chen, Y
EM: ygchen@ntu.edu.tw
AF: Department of Geosciences, National Taiwan University, No. 1, Roosevelt Rd., Sec. 4, Taipei, 106 Taiwan
AU: Chang, H
EM: chang.huicheng@seed.net.tw
AF: Central Geological Survey, MOEA, 2. Lane 109, Hua-Hsin Street, Chung-Ho, Taipei, 235 Taiwan
AB: The 1999 earthquake brought about 80-km-long surface ruptures along the Shihkang, Chelungpu, and Tajienshan Faults, central Taiwan. Several trenches have been excavated across the Chelungpu Fault of the middle segment. The surface ruptures display clear scarps ranging from 0.2 m to 4 m high, showing a complex geomorphic pattern due to coseismic faulting and folding. In the study, measurement of the vertical offset or structural relief was taken with reference to the hanging wall beyond the trishear deformation zone. Therefore we suggest that, for the measurement of offset, we should leave out the trishear zone, and that structural relief on the hanging wall should be represented as a real vertical offset. The net slip is then calculated from the structural relief and dip angle of the thrust on a vertical plane along the slip direction. By the excavation of the pineapple field across the Chelungpu Fault, we are able to first provide evidence of at least four earthquake events for the past about 1900 years, including the 1999 earthquake. Furthermore, based on the radiocarbon dates and historical record, the timing of the penultimate event is bracketed to be between 430 and 150 years ago, and the average recurrence interval smaller than 700 years. These data indicate that the average slip rate is about 8.7 mm/yr for the past 1900 years.
DE: 7221 Paleoseismology
DE: 8107 Continental neotectonics
DE: 9320 Asia
SC: Tectonophysics [T]
MN: 2003 Fall Meeting