Clustering

We have published a new paper on the fault geometry for the Mw 5.0 western Kanagawa earthquake in eastern Japan on 9 August 2024. We detected earthquakes using PhaseNet, relocated them with hypoDD, and applied our hypocenter clustering algorithm (Sawaki et al. 2025, JGR) . The results supports intraplate reverse faulting within the subducting Izu–Bonin arc, as opposed to interplate thrusting such as the 1923 Kanto Earthquake (Mw 8.2) or reverse faulting in the continental arc.

Check the paper below for details!

• Sawaki, Y., T. Shiina, and T. Uchide (2025). Steep intraplate reverse faulting adjacent to the hypocenter of the 1923 Kanto earthquake: The Mw 5.0 western Kanagawa earthquake in eastern Japan on 9 August 2024. Earth, Planets and Space, 77, 186. doi: 10.1186/s40623-025-02311-9 (Open Access)

We have posted a new preprint on the fault geometry for the Mw 5.0 western Kanagawa earthquake in eastern Japan on 9 August 2024. This is a preprint (peer-review not completed), but feel free to check it out!

Sawaki, Y., T. Shiina, and T. Uchide. Intraslab reverse faulting adjacent to the hypocenter of the 1923 Kanto earthquake: The Mw 5.0 western Kanagawa earthquake in eastern Japan on 9 August 2024 [Preprint v1]. Research Square. https://doi.org/10.21203/rs.3.rs-6353744/v1

We have estimated the fault geometry of the 2024 Noto Peninsula Earthquake in central Japan on 1 January 2024. Our analysis reveals major and minor fault planes aligned along the coastline beneath the peninsula. Notably, we identified a more counter-clockwise rotated plane in eastern Wajima and an east-dipping plane along the west coast. These localized structural complexities suggest intricate fault slip behavior and exhibit a strong correlation with gravity anomalies and geological structures. This research contributes to a deeper understanding of the formation and seismotectonics of the Noto Peninsula.

We also won the AIST President Award 2024 related to Contribution to National Earthquake Disaster Prevention Measures: Response to the 2024 Noto Peninsula Earthquake (in Japanese)!

Check the paper and software below!

• Sawaki, Y., T. Shiina, K. Sagae, Y. Sato, H. Horikawa, A. Miyakawa, K. Imanishi, and T. Uchide (2025). Fault Geometries of the 2024 Mw 7.5 Noto Peninsula Earthquake from Hypocenter-Based Hierarchical Clustering of Point-Cloud Normal Vectors. Journal of Geophysical Research: Solid Earth, 130, e2024JB030233. doi: 10.1029/2024JB030233 (Open Access)
• Sawaki, Y., Y. Sato, and T. Uchide (2025). FaultNVC: Earthquake Fault Plane Extractor through Point-Cloud Normal Vector Clustering for Hypocenter Distributions [Software]. Open-File Report of Geological Survey of Japan, AIST, no. 759. https://www.gsj.jp/publications/pub/openfile/openfile0759.html