M4.5 Earthquake 73 km NE of Yonakuni, Japan — April 21, 2023
2023-04-21 16:09:55 UTC (2023-04-21) · approx. 12:09 AM UTC+8 local
On April 21, 2023 at 16:09 UTC, a magnitude 4.5 intermediate depth earthquake struck 73 km NE of Yonakuni, Japan, at a depth of 112.7 km and coordinates 24.9834°, 123.4561°. This earthquake was detected by 49 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 312, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.5 releases seismic energy equivalent to roughly 85 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 767 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
123.4561°E
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Common Questions
How strong was the magnitude 4.5 earthquake near Yonakuni, Japan?
The magnitude 4.5 earthquake that struck 73 km NE of Yonakuni, Japan on April 21, 2023 at 16:09 UTC had a depth of 112.7 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 24.9834°, 123.4561°, which is 73 km NE of Yonakuni, Japan. View all earthquakes in Japan.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 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 4.5 event is significantly smaller than that historical record.
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Location
Authoritative source: USGS event page (event ID: us6000k658). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, April 21, 2023). M4.5 Earthquake 73 km NE of Yonakuni, Japan — April 21, 2023. Retrieved January 18, 2024 from https://www.earthquaketracker.org/earthquakes/event/us6000k658/