HR: 1340h
AN: S43C-1017    [Abstracts]
TI: Surface Rupture Segmentation and Slip Distribution of the 14 November 2001 Ms 8.1 Earthquake on the Kunlun Fault, Qinghai-Tibetan Plateau, China
AU: Ding, G
AF: State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Qijiahuozi, Dewai Avenue, Beijing, 100029 China
AU: Ding, G
AF: Center for Analysis and Prediction, China Earthquake Administration, No.63, Fuxing Avenue, Beijing, 100038 China
AU: * Chen, J
EM: chenjie@eq-igl.ac.cn
AF: State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Qijiahuozi, Dewai Avenue, Beijing, 100029 China
AU: Chen, Y
AF: State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Qijiahuozi, Dewai Avenue, Beijing, 100029 China
AU: Tian, Q
AF: Center for Analysis and Prediction, China Earthquake Administration, No.63, Fuxing Avenue, Beijing, 100038 China
AU: Wang, Z
AF: Qinghai Seismological Bureau, Xining, Xining, 810000 China
AU: Shan, X
AF: State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Qijiahuozi, Dewai Avenue, Beijing, 100029 China
AU: Ren, J
AF: State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Qijiahuozi, Dewai Avenue, Beijing, 100029 China
AU: Zhao, R
AF: Xinjiang Seismological Bureau, Urumqi, Urumqi, 830011 China
AU: Wang, Z
AF: State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Qijiahuozi, Dewai Avenue, Beijing, 100029 China
AB: The 14 November 2001 Ms =8.1 earthquake represent the most recent one of a series of large earthquakes along the Kunlun Fault, a highly active left-lateral strike-slip fault that bound the northern Tibet Plateau. Detailed surface rupture mapping, including 291 surficial left-lateral slip measurements and 111 net vertical slip measurements shows that the surface trace was 426 km long, multisegmented and consists of five major segments: the Taiyanghu, Buka Daban, Kusaihu West, Kusaihu East, and Kunlun Pass fault segments with the maximum left-lateral slip magnitudes 3, 5.7, 6, 6.4, and 4.2 m from west to east respectively, averaging 2.7 m. Two primary characteristics of the surface rupture are the en echelon geometry of the principle faults and the predominance of left-lateral strike slip, with local components of normal and reverse displacements caused by local changes in the fault geometry. Transtensional and transpressional structures were observed within releasing and restraining step-over areas respectively. The vertical slip components on all faults are less than 1 m (with as much as of 5.1 m vertical slip), quite variable and show little systematic behavior. Sinistral surficial slip was quite variable along the main trace of the rupture, however there is fairly regular long-wavelength (tens to hundreds of kilometers) behavior to the east of the Buka Daban Feng. Slips as large as 5~6 meters were observed at 5~6 sites that distributed at different surface rupture segments with the asymmetric shape of the slip profiles, which may be reflective of the direction rupture propagated. In additional, field and satellite images evidence indicates that most of the faults that ruptured in 2001 had had late Quaternary displacement. The variations in surficial slip (at both short and long length scales) which is only near-field slip using tape measures, should be considered minimum values and represent real variations in the amount of brittle slip on visible fractures at the surface, and potentially underestimates the actual slip for the earthquake and slip distribution for the overall surface rupture due to the difficulty in recognizing distributed nonbrittle deformation. This calls for caution in discriminating between one or multiple discrete events or estimating the size of past and future earthquakes using displaced deposits in trenches or offset geomorphologic features along strike-slip prehistoric fault ruptures.
DE: 9320 Asia
DE: 7230 Seismicity and seismotectonics
DE: 8110 Continental tectonics--general (0905)
DE: 8149 Planetary tectonics (5475)
SC: Seismology [S]
MN: 2004 AGU Fall Meeting