Abstract
Many source models for the 2011 Tohoku earthquake are derived by dense observation of teleseismic, strong motion, geodetic, and tsunami open data. We review similarity and difference of source models from strong motion records. Long-period source models in a period range of longer than around 10 s inverted large slip near the hypocenter and along the Japan Trench. On the other hand, short-period source models in a period range of shorter than around 10 s provided several strong motion generation areas or strong-motion pulse generation areas with large stress drop near the hypocenter and along the down-dip edge of the fault. Both source models are partly overlapped in the Miyagi-oki region, and complementary in the Fukushima-oki and Ibaraki-oki regions. Source models from back projection, array analyses, envelope inversion, and seismic intensity inversion generally agreed with the above mentioned source characteristics. Alike the 2010 Maule, Chile, earthquake, the 2011 Tohoku earthquake could be consist of M9-calss long-period and M8-class short-period source models. However, new findings of complex rupture along dip direction and multiple rupture over the fault indicate the diversity of earthquake source. The resolving power of strong motion dataset along the Japan Trench is not enough for the 2011 Tohoku earthquake, and further offshore strong motion observation is highly expected.
