HR: 15:10h
AN: T13E-06    [Abstracts]
TI: Asian Active Tectonics: A Finite Element Study
AU: * Wang, S
EM: wangshi@missouri.edu
AF: University of Missouri, Department of Geological Sciences, 101 Geological Sciences Building, Columbia, MO 65211 United States
AU: * Wang, S
EM: wangshi@missouri.edu
AF: Peking University, Department of Geophysics, Haidian, Beijing, 100871 China
AU: Liu, M
EM: lium@missouri.edu
AF: University of Missouri, Department of Geological Sciences, 101 Geological Sciences Building, Columbia, MO 65211 United States
AB: Asia is the largest region of intense intraplate deformation and seismicity. We have developed a 3D finite element model to investigate the driving forces, rheological structures, and boundary conditions that control the global pattern of strain rate and stress field in Asia. The model lithosphere is a 3D spherical shell of power law rheology, supported by a viscous foundation. Lateral variations of topography and crustal thickness are included explicitly in the model. At the Indian-Eurasian boundary the relative velocities from the Nuvel-1A model are imposed. A free slip boundary condition is assigned to the west ($60\deg$E) and north ($70\deg$N) boundaries of the model domain. At other boundaries, both a lithostatic stress condition and a free slip boundary condition are tested. Our results indicate that most of the Indian-Asian collisional force is absorbed within the Tibetan Plateau and surrounding regions, with little impact on active deformation in the region east of $100\deg$E. On the other hand, gravitational buoyancy forces from the high topography of the Tibetan Plateau and other part of central Asia have broad impact on active tectonics in all parts of Asia. The predicted strain rate pattern is highly sensitive to the rheology structure. We will show that geodetic measurements incorporated with proper geodynamic modeling could provide useful constraints on lithospherical rheology, thus improving our understanding of the dynamics of intraplate deformation in Asia.
DE: 8120 Dynamics of lithosphere and mantle--general
DE: 8122 Dynamics, gravity and tectonics
DE: 8159 Rheology--crust and lithosphere
DE: 8164 Stresses--crust and lithosphere
DE: 1208 Crustal movements--intraplate (8110)
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting