M4.8 Earthquake 48 km SE of Koseda, Japan — July 21, 2020
2020-07-21 08:54:25 UTC (2020-07-21) · approx. 5:54 PM UTC+9 local
Felt by 1 person across nearby locations.
On July 21, 2020 at 08:54 UTC, a magnitude 4.8 shallow crustal earthquake struck 48 km SE of Koseda, Japan, at a depth of 32.6 km and coordinates 30.1267°, 131.0476°.
Physical scale: An earthquake of magnitude 4.8 releases seismic energy equivalent to roughly 239 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.2 km — 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
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 1 citizen response to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
131.0476°E
Technical Information
Common Questions
How strong was the magnitude 4.8 earthquake near Koseda, Japan?
The magnitude 4.8 earthquake that struck 48 km SE of Koseda, Japan on July 21, 2020 at 08:54 UTC had a depth of 32.6 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 30.1267°, 131.0476°, which is 48 km SE of Koseda, Japan. View all earthquakes in Japan.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.8 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 4.8 event is significantly smaller than that historical record.
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Location
Authoritative source: USGS event page (event ID: us7000as7e). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, July 21, 2020). M4.8 Earthquake 48 km SE of Koseda, Japan — July 21, 2020. Retrieved September 26, 2020 from https://www.earthquaketracker.org/earthquakes/event/us7000as7e/