M4.2 Earthquake 12 km W of Hiroo, Japan — December 22, 2025
2025-12-22 20:03:48 UTC (2025-12-22) · approx. 6:03 AM UTC+10 local
On December 22, 2025 at 20:03 UTC, a magnitude 4.2 shallow crustal earthquake struck 12 km W of Hiroo, Japan, at a depth of 65.5 km and coordinates 42.2758°, 143.1513°.
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
143.1513°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.2 earthquake near Hiroo, Japan?
The magnitude 4.2 earthquake that struck 12 km W of Hiroo, Japan on December 22, 2025 at 20:03 UTC had a depth of 65.5 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: us7000rpy2). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, December 22, 2025). M4.2 Earthquake 12 km W of Hiroo, Japan — December 22, 2025. Retrieved May 23, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000rpy2/