EFFECT of colored noise on the generation of seismic fault MOVEMENT: Analogy with spring-block model DYNAMICS

Abstract

In present paper authors examined the effect of colored noise on the onset of seismic fault motion. For this purpose, they analyze the dynamics of spring-block model, with 10 all-to all coupled blocks. This spring-block model is considered as a collection of fault patches (with the increased rock friction), which are separated by the material bridges (more petrified parts of the fault). In the first phase of research, authors confirm the presence of autocorrelation in the background of seismic noise, using the measurement of real fault movement, and the recorded ground shaking before and after an earthquake. In the second stage of the research, authors firstly develop a mean-field model, which accurately enough describes the dynamics of a starting block model, with the introduced delayed interaction among the blocks, while colored noise is assumed to be generated by Ornstein-Uhlenbeck process. The results of the analysis indicate the existence of three different dynamical regimes, which correspond to three regimes of fault motion: steady stationary state, aseismic creep and seismic fault motion. The effect of colored noise lies in the possibility of generating the seismic fault motion even for small values of correlation time. Moreover, it is shown that the tight connection between the blocks, i.e. fault patches prevent the occurrence of seismic fault motion.