Crustal deformation in China and models comparison of the 2008 Wenchuan earthquake
Speaker: Yi-Xiu Lai
Abstract
Global Positioning System (GPS) measurements in China indicate that crustal shortening accommodates most of India's penetration into Eurasia. Deformation within the Tibetan Plateau and its margins, the Himalaya, the Altyn Tagh, and the Qilian Shan, absorbs more than 90% of the relative motion between the Indian and Eurasian plates. Internal shortening of the Tibetan plateau itself accounts for more than one-third of the total convergence. However, the Tibetan plateau south of the Kunlun and Ganzi-Mani faults is moving eastward relative to both India and Eurasia. This movement is accommodated through rotation of material around the eastern Syntaxis. A proper slip fault model and a reasonable dislocation theory are necessary to compute and investigate coseismic deformations caused by the 2008 Wenchuan earthquake (Ms 8.0). To find such a model, several comparisons are made of different dislocation theories, and seismic fault models. Results indicate that the fault model determined by combining GPS and seismic waveform data is the best. The spherical dislocation theory yields better results than that of a half-space theory. According to results of earlier investigations, co-seismic deformations such as the displacement, geoid, and gravity changes caused by the 2008 Wenchuan earthquake (Ms8.0) are computed, described, and discussed.
Reference
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