HR: 1330h
AN: T42B-0294    [PDF]
TI: Kinematic modeling of Neotectonic velocity field of the Persia-Tibet-Burma Orogen
AU: * Liu, Z
EM: zliu@ess.ucla.edu
AF: Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095 United States
AU: Bird, P
EM: pbird@ess.ucla.edu
AF: Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095 United States
AB: New kinematic finite-element program NeoKinema has been applied to compute the long-term-average velocity field and fault slip rates in the Persia-Tibet-Burma orogen using the Maximum-likelihood criterion. The orogen extends from east Turkey on the west, to Burma and Laos on the south, to east and southeast China on the east, and to Mongolia on the north. We use three data sets in our modeling: 1497 GPS benchmark solutions compiled from published sources, 366 geologic slip rates with standard deviations, 876 most compressive horizontal principal stress directions from the World Stress Map 2003 [Mueller et al., 2003]. Faults and potentially active faults are included. But faults of less constrained slip rates, e.g., faults in Iran, are assigned with large uncertainty. An iterative procedure is used to correct for transient fault locking effects on geodetic data. We use an updated plate model PB2002 to approximate the velocity boundary conditions from surrounding rigid plates (Anatolia, Arabia, India, Burma, Sunda, Yangtze, Amur) and the rigid part of the Eurasia plate in a Eurasia-fixed reference frame [Bird, 2003]. We also test various Sunda-Eurasia Euler poles and their effects on our modeling results. The F-E grid has 1564 nodes and 1964 triangular elements. So far 26 models have been computed with various background strain rates and weighting of GPS data. Initial results show a good correspondence between predicted strain rate and Harvard CMT earthquake catalogue with m$>$5.5. The preferred fault slip rates in central and southeast Asia are generally less than the geologic estimates but within $\pm$2$\sigma$ error bounds. The strain rate field and optimal fault slip rate estimates suggest that crustal deformation in the Persia-Tibet-Burma orogen is a mixture of distributed and quasi-rigid block deformation. A few such blocks are central Iran and southern Caspian basin, Tarim basin and Gobi platform, Qaidam basin, Ordos block and north of Tienshan in central Asia.
DE: 8102 Continental contractional orogenic belts
DE: 8107 Continental neotectonics
DE: 8110 Continental tectonics--general (0905)
SC: Tectonophysics [T]
MN: 2003 Fall Meeting