M4.9 Earthquake 128 km S of Honchō, Japan — December 31, 2025
2025-12-31 16:30:24 UTC (2025-12-31) · approx. 2:30 AM UTC+10 local
On December 31, 2025 at 16:30 UTC, a magnitude 4.9 shallow crustal earthquake struck 128 km S of Honchō, Japan, at a depth of 54.2 km and coordinates 40.9740°, 142.9453°. This earthquake was detected by 93 seismic stations with good location accuracy and was assigned a USGS significance rating of 369, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 km — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in Japan, a region characterized by the intersection of four tectonic plates — Pacific, Philippine Sea, Eurasian, and North American — creating multiple subduction zones. The nearest mapped fault system is the Japan Trench. View all earthquakes in Japan.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
142.9453°E
Technical Information
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Common Questions
How strong was the magnitude 4.9 earthquake near Honchō, Japan?
The magnitude 4.9 earthquake that struck 128 km S of Honchō, Japan on December 31, 2025 at 16:30 UTC had a depth of 54.2 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 40.9740°, 142.9453°, which is 128 km S of Honchō, Japan. View all earthquakes in Japan.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 earthquakes can continue for several days and gradually diminish over time.
Has Japan had earthquakes this big before?
The largest recorded earthquake in Japan was the M9.1 Tohoku earthquake of March 11, 2011. Today's magnitude 4.9 event is significantly smaller than that historical record.
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.
Authoritative source: USGS event page (event ID: us7000rlqw). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, December 31, 2025). M4.9 Earthquake 128 km S of Honchō, Japan — December 31, 2025. Retrieved May 16, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000rlqw/