Effects of fault geometry and dynamic parameters of spontaneous rupture on seismic wave field

The spontaneous rupture of faults and its resulting seismic wave field are important subject in seismological research. Different fault geometry and dynamic parameters in the spontaneous rupture process often lead to different rupture processes, which in turn have a significant impact on the seismic wave field. In this work, we computed the spontaneous rupture process on faults with different geometries, and analyzed the characteristics of the corresponding seismic wave field. Two kinds of fault systems which are bending and branching faults are considered. We investigated the impact of the position of the initial nucleation zone and supershear rupture on the seismic wave field for each system separately. The results show that for bending faults, as the bending angle increases, the peak distribution of the seismic wave field changes along the bending direction. Excessive bending angles will depress the seismic wave field. The longer the rupture distance on the faults is, the more energy will be accumulated, which will cause a larger seismic wave field. For branching faults, the branch plane with a smaller angle is more likely to rupture, and the rupture strength is greater, which will cause a stronger seismic wave field. The supershear rupture will also cause a stronger seismic wave field and excite high-frequency components. Obvious pulses can be observed and the permanent displacement will be increased. The results of this study is helpful to understand seismic wave field characteristics and provide more information for further dynamics inversion.