A two-dimensional earthquake fault modeling with fractal structure strength distribution

Abstract

In this paper a two-dimensional (2-D) model of earthquake fault rupturing was presented. It was estabilished on the basis of 1-D spring-block model. Using this model, we studied the dynamical plane-strain fracture problem, modeled the whole dynamical process of nucleating, expanding and propagating of fracture on a 2-D fault with homogeneous or inhomogeneous rupture strength distribution. Our studies show that under homogeneous prestress condition, the fault will gain enough momentum to tear strong obstacles in their propagating path. The rupturing fronts can also propagate forth around the isolated barriers. It is shown that the stopping conditions for rupturing processes play an important role in modeling whole earthquake process. We also studied the dynamical rupturing problems of the fault on which the rupture strength distribution is inhomogeneous, and modeled the earthquake sequence generated on a 2-D fault with the strength distribution of fractal structure. It possesses some similar features as a seismic sequence in the nature. These features mainly depend on the distribution of rupture strength on the fault plane and the level of initial stress drop. The modeling studies which were established on the basis of experiments and observations provided the physical basis for explaining some statistical rules of seismicity.