M4.5 Earthquake 123 km SSW of Itoman, Japan — August 28, 2021
2021-08-28 22:35:58 UTC (2021-08-28) · approx. 6:35 AM UTC+8 local
On August 28, 2021 at 22:35 UTC, a magnitude 4.5 shallow crustal earthquake struck 123 km SSW of Itoman, Japan, at a depth of 10.0 km and coordinates 25.1554°, 127.0627°.
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
127.0627°E
Technical Information
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Common Questions
How strong was the magnitude 4.5 earthquake near Itoman, Japan?
The magnitude 4.5 earthquake that struck 123 km SSW of Itoman, Japan on August 28, 2021 at 22:35 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 25.1554°, 127.0627°, which is 123 km SSW of Itoman, 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: us7000f8wl). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, August 28, 2021). M4.5 Earthquake 123 km SSW of Itoman, Japan — August 28, 2021. Retrieved November 6, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000f8wl/