[U-15] The 2024 Noto Peninsula Earthquake (1:J)

[U15-P55] Continuous observation of electromagnetic fields around the seismic swarm region in the northeastern Noto Peninsula

*Ryokei Yoshimura¹, Kenichi Yamazaki¹, Shintaro Komatsu¹, Tomoya Yamazaki¹, Nakagawa Jun¹, Rintaro Miyamachi¹, Masahiro Yoshikawa¹, Maki Hata¹, Yoshihiro Hiramatsu², Naoto Ishikawa³ (1.Disaster Prevention Research Institute, Kyoto University, 2.Kanazawa University, 3.Toyama University)

Keywords:Noto, seismic swarm, resistivity structure, temporal change

We have been conducting continuous electromagnetic field observations since the end of FY2022 in the northeastern Noto Peninsula, Ishikawa Prefecture, where seismic swarms and localized unsteady crustal deformation have been continuing since the end of 2020. This seismic swarm activity is considered to be related to the movement and diffusion of subsurface fluid, and we are attempting to capture the fluid dynamics through continuous observation of the electromagnetic field.
The continuous electromagnetic field observation network consists of two types of broadband electromagnetic field instruments (ELOG-MT and ELOG-Dual manufactured by NT System Design) that measure five components of the electromagnetic field and two components of the electric field and record electromagnetic field data at sampling intervals of 15 Hz, 150 Hz (UTC13:00-21:00), and 2400 Hz (UTC15:00-20:00). Continuous observations started at the end of FY2022 with one 5-component station and five 2-component stations, and a total of four stations were able to acquire pre- and post-earthquake long-term electromagnetic field records for the M6.5 earthquake on May 5, 2023, and the M7.6 earthquake on January 1, 2024, respectively.
Using the acquired electromagnetic field records, we plan to report whether long-term temporal changes in electromagnetic response are observed and whether short-term electromagnetic field signals exist before and after the earthquakes.