Recent news

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)

From this autumn, I teach the Earth Science Liberal Arts class by myself in Ritsumeikan University.

I attended the 22nd Annual Meeting of the Asia Oceania Geosciences Society (AOGS2025) in Singapore and IAGA/IASPEI Joint Scientific Meeting 2025 in Lisbon, Portugal. I was excited about my first visit to Singapore and European countries.

We published a new paper in Earth, Planets and Space about the aftershock distribution of the Mj7.6 Noto Peninsula earthquake on 1 January 2024.

This earthquake triggered extensive aftershocks. Previously, offshore aftershock locations were poorly constrained due to simplified velocity models. Our study used a 3D velocity model and Markov chain Monte Carlo to precisely determine hypocenters. Results show aftershocks occurred at 15 km depth or shallower, indicating the main rupture involved shallow submarine faults, contributing to tsunami generation. The aftershock distribution significantly differs from previous seismicity, suggesting a complex fault network across the peninsula influenced the Mj7.6 earthquake and subsequent activity, as suggested in Sawaki et al. (2025) .

Check the paper below for details!

• Shiina, T., H. Horikawa, Y. Sawaki, K. Sagae, and K. Imanishi (2025). Aftershock distribution of the 2024 Noto Peninsula Earthquake, Japan, determined using a 3D velocity structure and uncertainty quantification. Earth, Planets and Space, 77, 94. doi: 10.1186/s40623-025-02227-4 (Open Access)

I joined the Japan Geoscience Union (JpGU) Meeting 2025 , held at the Makuhari Messe in Chiba, JP, from 25 to 30 May 2025. I made an oral and a poster presentations.

• [SSS12-18] “Intraslab reverse faulting adjacent to the hypocenter of the 1923 Kanto earthquake: The Mw 5.0 western Kanagawa earthquake on 9 August 2024” by Sawaki, Y., T. Shiina, and T. Uchide
• [SSS06-P01] “Mutsu Bay Seismic Cluster along the Volcanic Front in November 2024” by Sawaki, Y., K. Sagae, T. Shiina, K. Imanishi, and T. Uchide

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

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.