The periodic and aperiodic slip during earthquake faulting and aseismic faulting slip: 1D fault model analysis

With a simple 1D spring-slide block model governed by Dieterich-Ruina law, this study derived an approximate analytical solution used to calculate the earthquake recurrence time and compared its approximate solution with previous results given by Barbot et al. The comparison between approximate solutions and the results by numerical simulation also demonstrated that current solution gives us a better approximation compared with previous result. Furthermore, it should be emphasized that, because only 40% to 80% of earthquake recurrence time belongs to interseismic stage, therefore, the duration of postseismic and nucleation/preseismic stage could not be ignored in the whole faulting process. Specifically, the time scale of earthquake recurrence in current earthquake recurrence model is not only related to the characteristic dimension of fault, the effective normal stress and remote loading rate, but also strongly depends on the values of the frictional parameters in the Dieterich-Ruina law and the critical distance obtained from laboratory. It is necessary to point out that, if all parameters we used represent a real situation in the earth, the approximate solution proposed in the present paper can give us an excellent estimation of earthquake recurrence time for a given tectonic region, of which relative error is less than 5%. Moreover, numerical simulation and theory are also used to study the mechanical mechanisms which cause the periodic and aperiodic evolution of the earthquake faulting and aseismic faulting slip. In addition, this paper also discussed the limitations and advantages of using 1D spring-slide block model to describe the elasticity in modeling evolution of fault. And it is found that applying shear stress loading during evolution of earthquake faulting can cause aperiodic evolution. Specially, applying shear stress loading at late nucleation/preseismic stage or early postseismic stage will lead to aseismic faulting slip.