M4.4 Earthquake 10 km S of Iwaizumi, Japan — December 21, 2025
2025-12-21 23:33:04 UTC (2025-12-21) · approx. 8:33 AM UTC+9 local
On December 21, 2025 at 23:33 UTC, a magnitude 4.4 shallow crustal earthquake struck 10 km S of Iwaizumi, Japan, at a depth of 67.3 km and coordinates 39.7525°, 141.8182°.
Physical scale: An earthquake of magnitude 4.4 releases seismic energy equivalent to roughly 60 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 655 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
141.8182°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.4 earthquake near Iwaizumi, Japan?
The magnitude 4.4 earthquake that struck 10 km S of Iwaizumi, Japan on December 21, 2025 at 23:33 UTC had a depth of 67.3 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 4.4 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 4.4 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000rwed). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, December 21, 2025). M4.4 Earthquake 10 km S of Iwaizumi, Japan — December 21, 2025. Retrieved May 23, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000rwed/