Japan Geoscience Union Meeting 2025

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[E] Poster

S (Solid Earth Sciences ) » S-CG Complex & General

[S-CG45] Science of slow-to-fast earthquakes

Wed. May 28, 2025 5:15 PM - 7:15 PM Poster Hall (Exhibition Hall 7&8, Makuhari Messe)

convener:Aitaro Kato(Earthquake Research Institute, the University of Tokyo), Asuka Yamaguchi(Atomosphere and Ocean Research Institute, The University of Tokyo), Ryoko Nakata(Graduate School of Science, The University of Tokyo), Kurama Okubo(National Research Institute for Earth Science and Disaster Resilience)

5:15 PM - 7:15 PM

[SCG45-P44] Stress Changes and Subsequent Earthquake Potential Following the 2024 Mw 7.5 Noto Peninsula Earthquake

*Mayuko Emori1, Ryosuke Ando1 (1.The University of Tokyo)


Keywords:the 2024 Noto Peninsula Earthquake

The aftershock distribution of the Mw 7.5 Noto Peninsula earthquake that occurred on January 1, 2024, extends approximately 150 km from northeast to southwest (Yoshida et al., 2024). It is estimated that the rupture propagated from the eastern part of the the Monzen-oki segment of the Monzen Fault Zone to the southwest part of the Western Margin Fault Zone of the Toyama Trough. In the Monzen-oki segment, the 2007 Mw 6.7 Noto Peninsula earthquake occurred. On November 26, 2024, 11 months after the mainshock, an Mw 6.2 earthquake occurred on the western Hakui-oki Nishi Fault. Since this event, seismic activity has remained active offshore west of Ishikawa Prefecture. In this study, we conducted a dynamic rupture simulation using FDP-BIEM (Ando, 2016, GJI) to investigate stress changes and the possibility of earthquake occurrence south of the Monzen-oki. For the analysis, we used a simplified fault geometry model, including the Western Margin Fault Zone of the Toyama Trough and the Hakui-oki fault. The regional stress field was set based on stress conditions obtained from stress tensor inversion analysis, uniform throughout Japan (Uchide et al., 2022, JGR). The preliminary results indicated that the Coulomb stress generated after the mainshock tended to increase on fault segments that did not rupture during the mainshock, including the Hakui-oki Nishi Fault. Notably, a significant increase in Coulomb stress was found near the rupture initiation point of the earthquake that occurred on November 26, 2024. In future work, we plan to improve the model to incorporate the effects of static stress changes from the 2007 earthquake, which were not directly considered in the preliminary analysis, as well as a more detailed geometric model of the fault branching area. This will allow us to examine the conditions for rupture propagation, reproduce fault activity south of the Monzen-oki segment, and conduct a trial forecast of its future evolution.