M4.3 Earthquake 263 km ESE of Onagawa Chō, Japan — September 27, 2025
2025-09-27 23:30:46 UTC (2025-09-27) · approx. 9:30 AM UTC+10 local
On September 27, 2025 at 23:30 UTC, a magnitude 4.3 shallow crustal earthquake struck 263 km ESE of Onagawa Chō, Japan, at a depth of 10.0 km and coordinates 37.7572°, 144.3239°.
Physical scale: An earthquake of magnitude 4.3 releases seismic energy equivalent to roughly 43 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 558 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
144.3239°E
Technical Information
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Common Questions
How strong was the magnitude 4.3 earthquake near Onagawa Chō, Japan?
The magnitude 4.3 earthquake that struck 263 km ESE of Onagawa Chō, Japan on September 27, 2025 at 23:30 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.3 earthquakes can continue for several days and gradually diminish over time.
What should I do after an earthquake?
If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.
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Understanding This Data
Magnitude 4.3 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000rhx6). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, September 27, 2025). M4.3 Earthquake 263 km ESE of Onagawa Chō, Japan — September 27, 2025. Retrieved May 28, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000rhx6/