M4.6 Earthquake near off the east coast of Honshu, Japan — December 12, 2021
2021-12-12 17:40:01 UTC (2021-12-12) · approx. 3:40 AM UTC+10 local
On December 12, 2021 at 17:40 UTC, a magnitude 4.6 shallow crustal earthquake struck near off the east coast of Honshu, Japan, at a depth of 10.0 km and coordinates 35.8265°, 144.2751°.
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
144.2751°E
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Common Questions
How strong was the magnitude 4.6 earthquake near off the east coast of Honshu, Japan?
The magnitude 4.6 earthquake that struck near off the east coast of Honshu, Japan on December 12, 2021 at 17:40 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 35.8265°, 144.2751°, which is near off the east coast of Honshu, 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.
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Location
Authoritative source: USGS event page (event ID: us6000gct0). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, December 12, 2021). M4.6 Earthquake near off the east coast of Honshu, Japan — December 12, 2021. Retrieved February 24, 2022 from https://www.earthquaketracker.org/earthquakes/event/us6000gct0/