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

[U15-P57] Temporal changes in the geomagnetic transfer functions
during the earthquake swarms in Noto Peninsula

*Jun Kawai¹, Miki Kawabata¹, Masakazu Miyamoto¹, Ryokei Yoshimura² (1.Applied Electronics Laboratory, Kanazawa Institute of Technology, 2.Disaster Prevention Research Institute, Kyoto University)

Keywords:earthquake swarms in Noto Peninsula, geomagnetic transfer function, SQUID

We have conducted highly sensitive observations of geomagnetic field in Suzu City, using a SQUID magnetometer system. The observation site was located in Karakasa-machi, close to the epicenters of the earthquake swarms. The observation periods ranged from 2022/4/29 to 2022/10/23, and from 2023/4/21 to 2023/12/7. We investigated the temporal changes in the geomagnetic transfer functions during the observation periods. By stacking four sections of 4096-second data from 15:00 to 20:00 (UT), which were resampled at 1 Hz from 200 Hz-sampled raw data, the daily geomagnetic transfer functions were calculated for the frequency. It was confirmed that the geomagnetic transfer functions at a period of 20 seconds to 50 seconds (0.02 Hz to 0.05 Hz) gradually changed over the period from August to December 2023.
The existence of a low-resistivity underground region has been suggested as a cause of the earthquake swarms (Nakajima 2022, Yoshimura 2022). In this presentation, we discuss whether this change in the geomagnetic transfer functions is related to the temporal change of the low- resistivity region.

Acknowledgments
We would like to thank Mr. Tetsuro Matsuda, the owner of Matsuda ranch.
The part of this research was supported by JSPS KAKENHI Grant Number 20K05053.