資源開発技術／開発機械／岩盤工学

[3K0101-10-07] Estimating the earthquake source mechanism using full waveform inversion

○Iktae Jang¹, Hitoshi Mikada¹, Junichi Takekawa¹ (1. Kyoto University)

司会：才ノ木 敦士（熊本大学）、羽柴 公博（東京大学）

Keywords:full waveform inversion, earthquake source mechanism, numerical experiment

An immediate understanding the source mechanism of an earthquake after the occurrence is an important task for the disaster mitigation to realize a safe society. One of the most important tasks for considering the mechanism of earthquake occurrence is estimating the earthquake source mechanism, and the centroid-moment tensor (CMT) solution has been widely used to estimate the focal mechanism so far. However, long term observation of spatial distribution of aftershocks is required to identify the nodal plane that caused the fault motion. Since the earthquake waveform caused by a nodal plane becomes different from that caused by the other conjugate nodal plane, the analysis of full waveform could be utilized to identify which nodal plane has caused the fault motion so that the focal mechanism of the earthquake could be estimated before the observation of aftershocks.

In this study, we try to apply a full waveform inversion (FWI) scheme to estimate focal parameters in the subsurface. We conduct numerical experiments based on the finite-difference method in order to demonstrate the effectiveness of the proposed approach. Our numerical results indicate that the FWI can be used to estimate earthquake parameters such as the location of the fault plane and distribution of dislocations.