[H-DS06] Tsunami and tsunami forecast

[HDS06-P12] Tsunami source of the 2007 Kuril earthquake inferred by joint inversion of seafloor pressure and seafloor magnetic data

*Rei Shibahara¹, Takuto Minami², Toshitaka Baba³, Hiroaki TOH⁴ (1.Department of Planetology, Graduate School of Science, 2.Division of Frontier Planetology, Department of Planetology, Graduate School of Science, Kobe University, 3.Graduate School of Science and Technology, Tokushima University, 4.Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University)

Keywords:tsunami, magnetic field

Along the northern Kuril trench, a great outer-rise earthquake occurred on January 13, 2007, two months after an interplate earthquake on November 15, 2006. Previous studies obtained models for the slip distribution of the fault that generated the tsunami of the 2007 outer-rise earthquake by the inversion using tide and seafloor pressure data (Fujii & Satake, 2008) or by the inversion using seafloor magnetic field data (Kawashima & Toh, 2016). In this study, we performed joint inversions using seafloor pressure data at two DART sites near Japan and three-component magnetic data obtained at a seafloor site in the northwest Pacific to obtain slip distributions explaining both data types simultaneously. The inversion using tsunami calculation based on the linear long wave theory resulted in a slip distribution that reproduced only the first wave of the observed waveform. The inversion using tsunami calculation based on the linear dispersive wave theory could not reproduce the first wave because of arrival time delay of the simulated tsunami relative to the observation, but it was able to generate the following wave. In the presentation, we report the detailed method and the results of our joint inversion for the source of the 2007 Kuril outer-rise earthquake.