Distribution Of Earthquake Fault Parameters And Projection Tomography Parameters Of Coulomb Stress Changes

Based on the calculation principle of static Coulomb failure stress change (△CFS) in the homogeneous elastic half-space, we calculated the influence of parameter change on the static△CFS. These parameters include dip, slip angle, dislocation, fault length, fault width, fault depth of earthquake fault, and strike, dip, slip angle, projection depth of projection fault. On this basis, we selected four types of earthquake fault model, and studied the characteristic of△CFS generated by different types of earthquake fault model. We also analyzed 96 actual earthquakes classified by fault type. In addition, we applied the study of the influence of various fault parameters to Yushu Ms7.1 earthquake, and discussed the influence of different source parameters on the calculate△CFS and its statistic relation with aftershocks.The results show that, except the fault depth, other earthquake fault parameters can cause the distribution of△CFS to change significantly. And among them, the most obvious is slip angle. Slip angle changes 45°, it can cause significantly change in the distribution of△CFS. Second is the earthquake fault dip. Dip has greater influence on the dip-slip earthquake fault's distribution of△CFS, but has no obvious influence on the strike-slip earthquake fault's. The earthquake fault's dislocation, fault length, fault width don't have a big influence on the distribution patterns of△CFS, while have a certain extent influence on the distribution range and intensity of△CFS. Earthquake fault depth, which changes in the 30km depth range, has no significantly influence. In the projection fault parameters, all of the strike, dip, slip angle, projection depth can cause significant changes in△CFS. Relatively speaking, the projection fault's dip has small influence on△CFS. Dip changes 45°, it can cause significantly changes in the distribution of△CFS. Projection fault depth can only cause greater influence on the distribution of△CFS near the fault, especially for negative change. The strike and slip angle of projection fault have more obvious influence on the distribution of△CFS.By studying the distribution of△CFS generated by various types of earthquake fault model, we found that the distributions of△CFS are different due to the different types of earthquake faults. Earthquake fault type directly affects Coulomb failure stress change's distribution patterns, intensity and distribution range. The distributions of△CFS generated by different types of actual earthquakes fault also basically conform to the conclusions of earthquake fault model. For the actual earthquake fault belonging to the same type, the distribution of△CFS also have the differences caused by fault parameters.