M4.5 Earthquake 10 km SSW of Ichihara, Japan — April 20, 2025
2025-04-20 06:11:07 UTC (2025-04-20) · approx. 3:11 PM UTC+9 local
Felt by 15 people across nearby locations.
On April 20, 2025 at 06:11 UTC, a magnitude 4.5 intermediate depth earthquake struck 10 km SSW of Ichihara, Japan, at a depth of 85.6 km and coordinates 35.4329°, 140.0380°. This earthquake was detected by 44 seismic stations with good location accuracy and was assigned a USGS significance rating of 316, 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
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 15 citizen responses 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
140.0380°E
Technical Information
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Common Questions
How strong was the magnitude 4.5 earthquake near Ichihara, Japan?
The magnitude 4.5 earthquake that struck 10 km SSW of Ichihara, Japan on April 20, 2025 at 06:11 UTC had a depth of 85.6 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 35.4329°, 140.0380°, which is 10 km SSW of Ichihara, 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: us6000q7ck). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, April 20, 2025). M4.5 Earthquake 10 km SSW of Ichihara, Japan — April 20, 2025. Retrieved September 6, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000q7ck/