[S-EM19] Electromagnetic Induction in the Earth and Planetary Interiors, and Tectono-Electromagnetism

[SEM19-10] Three dimensional resistivity structure around the focal region of the 2016 Kumamoto earthquakes

*Koki Aizawa¹, Hisashi Asaue², Katsuaki Koike³, Shinichi Takakura⁴, Toru Yoshinaga¹⁰, Makoto Uyeshima⁵, Takao Koyama⁵, Ryokei Yoshimura⁷, Ken'ichi Yamazaki⁷, Shintaro Komatsu⁷, Yusuke Yamashita⁷, Hiroshi Ichihara⁹, Mitsuru Utsugi⁸, Kaori Tsukamoto¹², Dan Muramatsu¹², Yoshiko Teguri^1,11, Kazunari Uchida¹, Hideaki Hase⁶, Azusa Shito¹, Satoshi Matsumoto¹, Takeshi Matsushima¹, Hiroshi Shimizu¹ (1.Institute of Seismology and Volcanology, Faculty of Sciences, Kyushu University, 2.Laboratory on Innovative Techniques for Infrastructures, Kyoto University, 3.Environmental Geosphere Engineering, Department of Urban Management, Graduate School of Engineering, Kyoto University, 4.Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, 5.Earthquake Research Institute, University of Tokyo, 6.GERD, 7.Disaster Prevention Research Institute, Kyoto University, 8.Aso Volcanological Laboratory, Institute for Geothermal Sciences, Graduate School of Science, Kyoto University, 9.Earthquake and Volcano Research Center, Graduate School of Environmental Studies, Nagoya University, 10.Kumamoto University, 11.Japan Meteorological Agency, 12.Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University)

Keywords:resistivity structure, magnetotellurics, Kumamoto earthquake

In December 2018, we have conducted broad-band magnetotelluric (MT) observation around Hinagu fault and Uto Peninsula, which are close to the focal regions of the 2016 M_JMA 7.3 Kumamoto earthquakes. Since the resistivity structure of these regions are not well imaged by the previous 3-D inversion by using the 80 MT sites (Aizawa et al., 2017, Sgepss fall meeting), we acquired the new data by using the Metronix ADU-07 system and the telluric loggers (NT System Design ELOG1K). We will present new 3-D resistivity structure and argue its relationship to the hypocenters that are relocated by using the double difference method and 3-D seismic velocity structure (Shito et al., 2017, GRL).



Acknowledgment

We are greatly indebted to the land owners for their permission for field campaigns. The geomagnetic data used for the remote-reference processing were provided by the Kakioka Geomagnetic Observatory of JMA. This work is partly supported by MEXT KAKENHI Grant Number JP16H06298, the Ministry of Education, Culture, Sports, Science and Technology of Japan under its Earthquake and Volcano Hazards Observation and Research Program, and Earthquake Research Institute, The University of Tokyo under Joint Usage Program.