[S-CG56] Dynamics in mobile belts

[SCG56-P08] Three-dimensional resistivity structure around Earthquake Swarm Region in the Northeastern Noto Peninsula

*Ryokei Yoshimura¹, Yoshihiro Hiramatsu², Tada-nori Goto³, Takafumi Kasaya⁴, Rintaro Miyamachi¹, Nakagawa Jun¹, Nagi Yamashita³, Rei Amano³, Masato Fukata², Amane Sugii², Taisei Inui¹, Ken'ichi Yamazaki¹, Shintaro Komatsu¹, Takuya Iwahori¹, Masahiro Yoshikawa¹, Ayako Namigishi¹, Nagaoka Airi¹, Yasuto Tatsuyama¹, Akihiro Sawada², Ce Zhang², Mitsuteru Fukuoka², Yuya Jinde², Yuki Oshima³, Momoka Kanazawa³ (1.Disaster Prevention Research Institute, Kyoto University, 2.Kanazawa University, 3.University of Hyogo, 4.Japan Agency for Marine-Earth Science and Technology)

Keywords:Noto, seismic swarm, resistivity structure

Earthquake swarm activity and localized non-steady crustal deformation have continued near Suzu city, Ishikawa Prefecture, since the end of 2020. This activity began around June 2018, with a M5.1 (maximum seismic intensity of 5-lower) earthquake on September 16, 2021, and a M5.4 (maximum seismic intensity of 6-lower) earthquake on June 19, 2022, and has shown no sign of abating.
We are conducting a subsurface resistivity structure survey to elucidate the structural location of this swarm activity and to determine whether there are structural differences from the area where the 2007 Noto Hanto earthquake occurred. The resistivity structure inferred from the onshore broadband electromagnetic field data reveals the existence of a continuous low resistivity zone from the southern cluster, where a series of seismic activity started, to the northern cluster, which is currently the most active, strongly suggesting fluid involvement in this activity.
In this presentation, we will report the results of the reanalysis with the addition of data from supplemental observations conducted at sea and land for the purpose of improving the resolution of the subsurface structure (three observations on the ocean bottom: from September to October 2022 and 23 observations on the land: from November 2022 to February 2023).