M4.2 Earthquake 90 km SSE of Koshima, Japan — May 25, 2026
2026-05-25 19:45:40 UTC (2026-05-25) · approx. 4:45 AM UTC+9 local
On May 25, 2026 at 19:45 UTC, a magnitude 4.2 shallow crustal earthquake struck 90 km SSE of Koshima, Japan, at a depth of 35.3 km and coordinates 29.4365°, 130.7211°.
Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 m — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.1 mainshock that occurred 2 days ago 101 km S of Yudomari, Japan. Since the mainshock, the USGS has recorded 0 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
130.7211°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.2 earthquake near Koshima, Japan?
The magnitude 4.2 earthquake that struck 90 km SSE of Koshima, Japan on May 25, 2026 at 19:45 UTC had a depth of 35.3 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 4.2 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.1 one earlier?
No. This magnitude 4.2 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier 101 km S of Yudomari, Japan. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 4.2 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000spw3). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, May 25, 2026). M4.2 Earthquake 90 km SSE of Koshima, Japan — May 25, 2026. Retrieved August 5, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000spw3/