M4.3 Earthquake 87 km SE of Onagawa Chō, Japan — August 8, 2025
2025-08-08 23:24:29 UTC (2025-08-08) · approx. 8:24 AM UTC+9 local
On August 8, 2025 at 23:24 UTC, a magnitude 4.3 shallow crustal earthquake struck 87 km SE of Onagawa Chō, Japan, at a depth of 58.6 km and coordinates 37.7930°, 142.0056°.
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
142.0056°E
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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 87 km SE of Onagawa Chō, Japan on August 8, 2025 at 23:24 UTC had a depth of 58.6 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.
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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: us7000qtba). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, August 8, 2025). M4.3 Earthquake 87 km SE of Onagawa Chō, Japan — August 8, 2025. Retrieved October 25, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000qtba/