HR: 1340h
AN: T43B-1339    [Abstracts]
TI: Ground Displacements and Fault-plane Geometry beneath: a case of 1999 Chi-Chi Earthquake (Mw 7.6) at Tsaotun in Central Taiwan
AU: * Kuo, Y
EM: yutingkuo@ntu.edu.tw
AF: Dept. of Geosciences, National Taiwan Univ., No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
AU: Huang, M
EM: r93224213@ntu.edu.tw
AF: Dept. of Geosciences, National Taiwan Univ., No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
AU: Chen, Y
EM: ygchen@ntu.edu.tw
AF: Dept. of Geosciences, National Taiwan Univ., No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
AU: Avouac, J
EM: avouac@gps.caltech.edu
AF: Division of Geological and Planetary Sciences, Caltech, Mail Code 100-23, Pasadena, CA 91125, United States
AB: Long-term ground deformation recorded in deformed geomorphic surfaces is supposed to be the cumulative strain produced by associated active structure and certainly related to the subsurface structure geometry. Moreover, by time domain the deformation also can be divided into components: co-, post-, and inter-seismic. A case that may demonstrate the entire process is at Tsaotun in central Taiwan, where widely developed geomorphic surfaces have long been noticed and surface ruptures of 1999 Taiwan Chi-Chi earthquake (Mw 7.6) ran though. Landform investigation, geodetic work, sub-pixel comparison of aerial photos, and D-InSAR analysis are conducted to reconstruction the entire deformation process mentioned above. In our previous study, we have used sub-pixel correlation on high-resolution aerial photographs to obtain detailed horizontal displacement across the surface ruptures, which has revealed that the fault bends beneath greater and more rapid in the southern segment. Nevertheless, the coseismic ground displacement cannot entirely match the long-term surface deformation recorded in the geomorphic surfaces. However, by the post-seismic ground displacements obtained from InSAR a few other active structures, such as secondary strike-slip faults, may play a role to accommodate the tentative stress accumulation in a large earthquake. By available co- and post-seismic ground displacements, we successfully rebuild a fault-plane model at Tsaotun. Using this model we can satisfactorily explain the surface deformation in different time domain. The model also describe the details of when, where, and how much the rate of the ground displacements would occur. Our result is undoubtedly valuable to improve the building code and to assist urbanization plan for the purpose of seismic hazard mitigation.
DE: 8000 STRUCTURAL GEOLOGY
DE: 8020 Mechanics, theory, and modeling
DE: 8040 Remote sensing
DE: 8100 TECTONOPHYSICS
SC: Tectonophysics [T]
MN: 2007 Fall Meeting