Dynamic rupture simulation of the 2011 off the Pacific coast of Tohoku Earthquake: Multi-event generation within dozens of seconds

We focus on a complex rupture process, namely, multi-event generation within about 50 seconds during the 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0). We perform a 2D dynamic rupture simulation in order to explain physically the rupture process along the cross-section passing through the hypocenter. Realistic velocity structures are introduced into the simulation model. The dynamic parameters are selected by referring to kinematic source inversion results. The first significant event is generated on the deeper side of the fault. The scattered waves, mainly from the free surface, generate a stick-slip around the hypocenter, and then a second significant event is triggered. The synthetic waveforms consist of two major wave groups that are consistent with the observed ground motions.