M4.6 Earthquake 13 km NNE of Uken, Japan — March 20, 2026
2026-03-20 21:19:21 UTC (2026-03-20) · approx. 6:19 AM UTC+9 local
On March 20, 2026 at 21:19 UTC, a magnitude 4.6 shallow crustal earthquake struck 13 km NNE of Uken, Japan, at a depth of 58.7 km and coordinates 28.4110°, 129.2947°. This earthquake was detected by 73 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
129.2947°E
Technical Information
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Common Questions
How strong was the magnitude 4.6 earthquake near Uken, Japan?
The magnitude 4.6 earthquake that struck 13 km NNE of Uken, Japan on March 20, 2026 at 21:19 UTC had a depth of 58.7 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 28.4110°, 129.2947°, which is 13 km NNE of Uken, 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: us6000shyj). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, March 20, 2026). M4.6 Earthquake 13 km NNE of Uken, Japan — March 20, 2026. Retrieved May 13, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000shyj/