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Title:: Inversion of Seismic Parameters of the Wenchuan Earthquake and Analysis on Variation of its Coulomb Stress Based on GPS observation

Author(s):: ZHANG Xi¹; 2; CUI Du-xin²; JIANG Feng-yun²; (1.Institute of Earthquake Prediction of CEA,Beijing 100036,China)(2.The Second Monitoring and Application Center of CEA,Xi'an 710054,Shaanxi,China)

Keywords:: the great Wenchuan earthquake; parameters inversion; Coulomb stress; dislocation

摘要:: 利用汶川M_S8.0地震前后的GPS观测资料,借助Okada矩形位错模型反演汶川地震参数,进而应用反演所得地震参数,计算地震在其周围GPS资料负位错反演所得震前应变积累断层段上可能造成的库仑破裂静应力变化,分析地震对其周围构造断裂应变积累的影响。结果表明,汶川震区呈显著逆冲兼右旋走滑同震变化,对甘川交界东段—甘川陕交界区、鲜水河断裂南段与安宁河断裂北端应变积累有一定程度影响,可能以增强作用为主。

Abstract:: In this paper,using the GPS observational data before and after the great Wenchuan earthquake on 12 May 2008,aided by rectangle dislocation model,the seismic parameters of this earthquake are obtained.Applying these parameters,the variation of Coulomb rupture static stress caused by this earthquake,is acted on its peripheral fault segments reflecting strain accumulation,before this earthquake revealed by the inversion of negative dislocation from GPS data.The influences of this great earthquake on strain accumulation of peripheral tectonic faults are researched.The result shows that,this earthquake region displayed remarkable co-seismic deformation of thrust and dextral slip.This great earthquake affected the eastern boundary where Gansu and Sichuan provinces meet and the boundary where Gansu,Sichuan and Shaanxi provinces meet,together with the southern segment of Xianshuihe fault and the northern end of Anninghe fault,to some degree,mainly reflecting possible enhanced action for strain accumulation.