HR: 0800h
AN: S31C-0562    [Abstracts]
TI: Estimations of Fault Parameters of the 2004 Sumatra Earthquake
AU: * Chang, W
EM: wychang@nsc.gov.tw
AF: National Science Council, Taipei, Taipei, 106, Taiwan
AU: Hwang, R
AF: Chinese Culture Univ., Taipei, Taipei, 111, Taiwan
AU: Chen, C
AF: National Chung Cheng Univ., Chia-Yi, Chia-Yi, 621, Taiwan
AU: Chang, J
AF: Hsing-Kuo Univ., Tainan, Tainan, 709, Taiwan
AU: Lin, T
AF: Central Weather Bureau, Taipei, Taipei, 100, Taiwan
AB: The rupture directivity for the 2004 Sumatra earthquake is analyzed by the differences of phase-delay time of Rayleigh-wave between the main shock and its nearby earthquakes at periods of 140-160 sec. A long source- process time (~463.0 sec) and large rupture length (~1164.0 km) are derived through the rupture directivity analysis. The source-process time for this earthquake is larger than those for the 1960 Chile and 1964 Alaska earthquakes. This might be due to the long rupture occurring during the faulting of the earthquake. The estimated rise time, 92.0 sec, for the 2004 Sumatra earthquake is approximately 20% of the whole source duration and is larger than those for the 1960 Chile and the 1964 Alaska earthquakes. This probably reflects a fundamental difference of frictional properties between these earthquakes. When taking the rise time into account, the estimated rupture velocity is approximately 3.1 km/sec, which is higher than previous studies from hydroacoustic data and regional seismic network. In this study, additional evidences from surface-wave phase-delay time analysis would confirm the basic features of rupture for the 2004 Sumatra earthquake. This result can also provide constraints on the study of source rupture for this earthquake.
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
SC: Seismology [S]
MN: 2007 Fall Meeting