Three-dimensional resistivity structure in the focal region of 2000 Western Tottori Earthquake

中村 謙佑*; 相澤 広記*; 浅森 浩一; 大志万 直人*; 井上 智裕*; 臼井 嘉哉*; 市原 寛*; 山口 雅弘*; 宇都 智史*; 畑岡 寛*; et al.

no journal, , 

We present the resistivity structure around the focal region of the 2000 Western Tottori Earthquake (M7.3) to investigate the relationship between the mainshock rupture and the resistivity stricture. The Western Tottori Earthquake occurred on October 6, 2000, in an area without surface faulting. Deep low-frequency earthquakes were observed approximately 8 km west of the epicenter at depths of around 30 km. To obtain a detailed resistivity structure, we conducted additional observations at 35 sites between October and December 2024, including 21 telluric-only sites. For our three-dimensional resistivity analysis, we utilized MT data from 52 sites used in previous study, 12 sites observed in 2001 by Kyoto University and Tottori University, and the newly added 35 sites. As a result, we identified a low-resistivity zone directly beneath the epicenter. We discuss the relationship between this resistivity structure, the slip distribution of the mainshock, and the occurrence of aftershocks.