Effects of fault movement and material properties on deformation and stress fields of Tibetan Plateau
Yong Zheng1, Xiong Xiong1, Yong Chen2, Bin Shan1
1 Key Laboratory of Dynamic Geodesy, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China 2 Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
Effects of fault movement and material properties on deformation and stress fields of Tibetan Plateau
Yong Zheng1, Xiong Xiong1, Yong Chen2, Bin Shan1
1 Key Laboratory of Dynamic Geodesy, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China 2 Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
摘要We compare the factors which affect the movement of Tibetan Plateau by building three types of finite element models: an elastic materials (M-EC), a continuous model composed by non-linear materials (M-PC), and an elastic model with discontinuous fault movements (M-ET). Both in M-ET and M-EC, the materials in Qiangtang and Lhasa block are elastic, and in M-ET, discontinuous movement of faults is considered for evaluating the effects of strike-slip faults. In model M-PC Druker-Prager plastic materials are used in Qiangtang and Lhasa block. Comparisons of the numerical simulation and the GPS observations show following characteristics: (1) Under present tectonic environment, short-term deformation of Tibetan Plateau can be simulated well by elastic models; (2) Discontinuous fault activities increase the lateral extrusion of the eastern part of Tibetan Plateau, reduce the stress field level in Qiangtang, Tarim and Qaidam blocks and strengthen the E-W extensional force in the east and the west parts of Qiangtang block; (3) Properties of plastic materials reduce the total stress field and the E-W extensional force, thus, the normal fault earthquakes in southern Tibet is mainly owed to the effect of active fault movement. Based on the numerical simulations we speculate that faults movement may play a more important role on the kinematic pattern of Tibetan Plateau than bulk properties.
Abstract：We compare the factors which affect the movement of Tibetan Plateau by building three types of finite element models: an elastic materials (M-EC), a continuous model composed by non-linear materials (M-PC), and an elastic model with discontinuous fault movements (M-ET). Both in M-ET and M-EC, the materials in Qiangtang and Lhasa block are elastic, and in M-ET, discontinuous movement of faults is considered for evaluating the effects of strike-slip faults. In model M-PC Druker-Prager plastic materials are used in Qiangtang and Lhasa block. Comparisons of the numerical simulation and the GPS observations show following characteristics: (1) Under present tectonic environment, short-term deformation of Tibetan Plateau can be simulated well by elastic models; (2) Discontinuous fault activities increase the lateral extrusion of the eastern part of Tibetan Plateau, reduce the stress field level in Qiangtang, Tarim and Qaidam blocks and strengthen the E-W extensional force in the east and the west parts of Qiangtang block; (3) Properties of plastic materials reduce the total stress field and the E-W extensional force, thus, the normal fault earthquakes in southern Tibet is mainly owed to the effect of active fault movement. Based on the numerical simulations we speculate that faults movement may play a more important role on the kinematic pattern of Tibetan Plateau than bulk properties.
基金资助:Chinese Academy of Sciences (Nos.KZCX2-YW-116 and KZCX2-YW-142), National Natural Science Foundation of China (Nos.40974034 and 40064004)
通讯作者:
Yong Zheng
E-mail: zhengyong@whigg.ac.cn
引用本文:
Yong Zheng, Xiong Xiong, Yong Chen, Bin Shan. Effects of fault movement and material properties on deformation and stress fields of Tibetan Plateau[J]. 《地震学报》英文版, 2011, 24(2): 185-197.
Yong Zheng, Xiong Xiong, Yong Chen, Bin Shan. Effects of fault movement and material properties on deformation and stress fields of Tibetan Plateau. Earthquake Science, 2011, 24(2): 185-197.
