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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

I started my career as an assistant professor at Ritsumeikan University, Japan.

I attended the Slow-to-Fast Eq A03 & B03 Groups Meeting in Hirosaki, North Japan, from Feb. 6 to 9, 2025. The diverse generations represented among attendees contributed to a highly engaging discussion.

I participated in American Geophysics Union Annual Meeting 2024 held in Washington D.C. during 9–13 December 2024 and gave an oral talk about the fault geometry of the 2024 Mw 7.5 Noto Peninsula Earthquake. Interactions with researchers and students ignited my passion for further research.

I visited Noto Peninsula in central Japan, where M7.6 earthquake occurred on 1 Jan 2024. I saw the great uplift on the western coast and surface rupture in the eastern area.

I participated in the 2024 Seismological Society of Japan (SSJ) Fall Meeting , held at the Toki Messe in Niigata City, JP, from Oct. 21 to 23. I made a following oral presentation.

• S22-03 “Fault Geometries of the 2024 Mw 7.5 Noto Peninsula Earthquake from Hypocenter-Based Hierarchical Clustering” Sawaki et al.

We imaged the slab and crustal structure of the Kii Peninsula in SW Japan using a receiver-function-like analysis. Positive impedance contrasts in the forearc crust correspond to the top surface or inside Kumano pluton, which may control fluid conditions around slow-earthquake sources.

Check it out below!

• Sawaki, Y., Y. Ito, E. S. M. Garcia, A. Miyakawa, and T. Shibutani (2024). Deep plutonic bodies over low-frequency earthquakes revealed from receiver-side Green’s functions. Tectonophysics, 892, 230536. doi: 10.1016/j.tecto.2024.230536 (Open Access)

I participated in the Japan Geoscience Union (JpGU) Meeting 2024 , held at the Makuhari Messe in Chiba, JP, from May 26 to 31. I made two presentations: one for oral and the other for poster.

• [SCG50-02] Multiscale Fault Estimation in California and Oklahoma. Sawaki, Y., D. Shelly, T. Uchide, K. Sagae, T. Shiina, Y. Sato, and H. Horikawa
• [U15-P09] Fault geometries of the 2024 Noto Peninsula earthquake estimated by hypocenter clustering. Sawaki, Y., T. Uchide, T. Shiina, K. Sagae, H. Horikawa, and K. Imanishi

We have a new preprint on the seismic structure beneath the Kii Peninsula, southwestern Japan, available on SSRN. While it’s not yet peer-reviewed, feel free to check it out if you’re interested!

Sawaki, Y., Y. Ito, E. S. M. Garcia, A. Miyakawa, and T. Shibutani. Deep Plutonic Bodies Over Low-Frequency Earthquakes Revealed from Receiver-Side Green’s Functions. Available at SSRN: http://dx.doi.org/10.2139/ssrn.4793654

SF-A03 Group Workshop at Toyama was held from Feb. 08–10, 2024. I gave a talk about “Hypocenter-based Visualization of Multiscale Earthquake Faults”.

The presentations on geology related to the mechanism of tectonic tremors were interesting to me. As a research collaborator of group A03, I would like to contribute to the comparative subduction zone studies of Slow-to-Fast earthquakes!