ABSTRACT:

This paper describes the three-dimensional numerical modeling of in situ stress distributions in a limited seismic region of the Earth's crust. The model involves a vertical strike-slip planar fault that resides in the crust and reaches the Earth's surface. Stress distribution in faulted areas can be calculated and then used to assess the potential of regional seismic hazard. The second goal of this study is application of a constitutive relation which represents the governing equation of the failure process and specifies the dependence between stress, fault slip, slip rate, and other relevant physical properties. There are several laboratory-derived friction constitutive laws among which the slip-weakening was adopted in this paper to simulate the failure process based on stick-slip behavior of faults. The finite element code (ABAQUS) is used to model the mechanical behavior of fault illustrating the distribution of stress and deformation in the crust.

1 INTRODUCTION

The dynamic rupture along a fault during an earthquake is a highly complex process involving many factors such as fault geometry, the initial stress field and the constitutive law. Since most of earthquakes occur by sudden slippage along pre-existing faults, the frictional behavior of faults and the constitutive friction law is the main factor in earthquake mechanism (Scholz 1998). There are several frictional laws which express the stick-slip behavior such as Amontons-Coulomb friction law (Jeager, Cook et al. 2007; Voisin, Renard et al. 2007), slip-weakening lawinwhich coefficient of friction is dependent on slip (MariagiovannaGuatteri & PaulSpudich 2000; Senatorski 2002; Olsen-Kettle, Weatherley et al. 2008; Liu & Shi 2009) and rate and state friction law (Chen & Lapusta 2008). All of these constitutive laws are derived from laboratory experiments. In this study, linear slip weakening law is adopted to simulate the frictional behavior of fault.

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