Dynamic Rupture Front Interaction on 3D Planar Fault

We demonstrate a rupture front focusing phenomenon at the initial stage of earthquake, which causes high slip rate pulses and therefore generates high frequency seismic waves. In this computation, we assume a pre-slip region, where stress has already lowered quasi-statically to the dynamic friction level. And due to the pre-slip, we suppose a stress concentration at the edge of pre-slip area. Then a dynamic rupture starts at a certain point on the rim of the pre-slip region. We could observe a rupture front focusing that causes high slip rate pulse. We also observed a high frequency pulse in ground velocity seismogram. We computed a double pre-slip model, where two pre-slip region exist, and found that multiple pre-slips enhances this eeect.