Strong Ground Motion Distribution and Simulation Based on Finite Fault Model of Lushan 7.0 Earthquake on April 20, 2013
详细信息
- 责任者：Zhang Dongli (Key Laboratory of Active Tectonics and Volcano ; Institute of Geology ; China Earthquake Administration ; Beijing 100029 ; China) ; Huang Bei
- 刊名：Seismology and Geology
- 出版年：2013
- 卷期：35(2)
- 关键词：大震 ; great earthquakes ; 断层 ; faults ; 四川 ; Sichuan Province
- 页码：p.423-435
- 图表：illus., 1 table, 29 refs.
- 分类号：0500
- issnNo：ISSN0253-4967
- isbnNo：CN11-2192/P
摘要
Field investigation and damage evaluation of the Lushan M7. 0 earthquake have revealed that the seismogenic fault of this earthquake is a typical blind fault with thrust component and there is no distinct surface rupture or deformation zone. The earthquake caused severe damage and failure such as mountain landslide,bedrock collapse,sand liquefaction on near-fault region and tensional fractures. In order to estimate the influence of strong ground motion on damage distribution,based on the inversion of slip distribution and rupture process on the source fault of the Lushan 7. 0 earthquake, strong ground motion simulation is carried out with finite-fault model and three-dimension crust model of Lushan area and its adjacent region. In the finite-fault model,the rupture source is characterized as a low-angle fault plane with inhomogeneous slip distribution. The maximum slip on fault plane is up to 150cm. For the three-dimension crust model,deep fault structure,steep terrain and basin have been taken into account and described by different physical parameters. In this paper,the numerical simulation results of strong ground motion about Lushan main earthquake reveal two following major characters. The first is that the distribution characteristics of peak acceleration values,peak velocities and peak displacements on the ground surface shows good consistency with the seismic damage investigation. On the hanging-wall of the causative fault,high intensity of strong ground motion mainly concentrates on Baosheng,Longmen and the northern area of Lushan,which are located within the IX meizoseismal area. Around the area of Longmen town,the maximum acceleration of UD component reaches up to 350gal and the maximum transient displacement is up to 110cm,which are consistent with recordings and investigations. The second conclusion from simulation results is that the strong ground distribution and propagation process are influenced by basin effect and steep terrain. Seismic wave propagated back and forth in intermountain basins,combining with the amplification of thin soil layers,which directly caused and increased the earthquake damage.
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