M4.5 Earthquake 70 km SSW of Yonakuni, Japan — March 8, 2023
2023-03-08 18:32:20 UTC (2023-03-08) · approx. 2:32 AM UTC+8 local
On March 8, 2023 at 18:32 UTC, a magnitude 4.5 shallow crustal earthquake struck 70 km SSW of Yonakuni, Japan, at a depth of 28.1 km and coordinates 23.9272°, 122.6314°. This earthquake was detected by 31 seismic stations with good 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
122.6314°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 70 km SSW of Yonakuni, Japan on March 8, 2023 at 18:32 UTC had a depth of 28.1 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 23.9272°, 122.6314°, which is 70 km SSW 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: us7000ji95). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, March 8, 2023). M4.5 Earthquake 70 km SSW of Yonakuni, Japan — March 8, 2023. Retrieved May 15, 2023 from https://www.earthquaketracker.org/earthquakes/event/us7000ji95/