M4.6 Earthquake 98 km ENE of Yokohama, Japan — December 9, 2025
2025-12-09 23:04:36 UTC (2025-12-09) · approx. 8:04 AM UTC+9 local
On December 9, 2025 at 23:04 UTC, a magnitude 4.6 shallow crustal earthquake struck 98 km ENE of Yokohama, Japan, at a depth of 53.8 km and coordinates 41.2729°, 142.3925°. This earthquake was detected by 85 seismic stations with good location accuracy and was assigned a USGS significance rating of 326, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.6 releases seismic energy equivalent to roughly 120 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 899 m — 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
142.3925°E
Technical Information
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Common Questions
How strong was the magnitude 4.6 earthquake near Yokohama, Japan?
The magnitude 4.6 earthquake that struck 98 km ENE of Yokohama, Japan on December 9, 2025 at 23:04 UTC had a depth of 53.8 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 41.2729°, 142.3925°, which is 98 km ENE of Yokohama, Japan. View all earthquakes in Japan.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.6 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 4.6 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: us6000rtra). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, December 9, 2025). M4.6 Earthquake 98 km ENE of Yokohama, Japan — December 9, 2025. Retrieved May 24, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000rtra/