M4.5 Earthquake 69 km ESE of Ishinomaki, Japan — October 4, 2021
2021-10-04 21:06:32 UTC (2021-10-04) · approx. 6:06 AM UTC+9 local
On October 4, 2021 at 21:06 UTC, a magnitude 4.5 shallow crustal earthquake struck 69 km ESE of Ishinomaki, Japan, at a depth of 45.5 km and coordinates 38.1597°, 142.0234°.
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
142.0234°E
Technical Information
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Common Questions
How strong was the magnitude 4.5 earthquake near Ishinomaki, Japan?
The magnitude 4.5 earthquake that struck 69 km ESE of Ishinomaki, Japan on October 4, 2021 at 21:06 UTC had a depth of 45.5 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 38.1597°, 142.0234°, which is 69 km ESE of Ishinomaki, 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: us6000frpm). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, October 4, 2021). M4.5 Earthquake 69 km ESE of Ishinomaki, Japan — October 4, 2021. Retrieved December 10, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000frpm/