M4.2 Earthquake 88 km SSE of Onagawa Chō, Japan — February 20, 2026
2026-02-20 18:59:32 UTC (2026-02-20) · approx. 3:59 AM UTC+9 local
On February 20, 2026 at 18:59 UTC, a magnitude 4.2 shallow crustal earthquake struck 88 km SSE of Onagawa Chō, Japan, at a depth of 51.4 km and coordinates 37.7788°, 142.0091°.
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.
Earthquake Details
142.0091°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.2 earthquake near Onagawa Chō, Japan?
The magnitude 4.2 earthquake that struck 88 km SSE of Onagawa Chō, Japan on February 20, 2026 at 18:59 UTC had a depth of 51.4 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.
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 4.2 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000sai0). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, February 20, 2026). M4.2 Earthquake 88 km SSE of Onagawa Chō, Japan — February 20, 2026. Retrieved May 18, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000sai0/