M4.7 Earthquake 79 km W of Tomamae, Japan — July 26, 2023
2023-07-26 21:31:31 UTC (2023-07-26) · approx. 6:31 AM UTC+9 local
On July 26, 2023 at 21:31 UTC, a magnitude 4.7 intermediate depth earthquake struck 79 km W of Tomamae, Japan, at a depth of 231.2 km and coordinates 44.3478°, 140.6645°. This earthquake was detected by 162 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 340, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.7 releases seismic energy equivalent to roughly 169 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.1 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
Earthquake Details
140.6645°E
Technical Information
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Common Questions
How strong was the magnitude 4.7 earthquake near Tomamae, Japan?
The magnitude 4.7 earthquake that struck 79 km W of Tomamae, Japan on July 26, 2023 at 21:31 UTC had a depth of 231.2 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 44.3478°, 140.6645°, which is 79 km W of Tomamae, Japan. View all earthquakes in Japan.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.7 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 4.7 event is significantly smaller than that historical record.
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Location
Authoritative source: USGS event page (event ID: us6000kvsp). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, July 26, 2023). M4.7 Earthquake 79 km W of Tomamae, Japan — July 26, 2023. Retrieved January 18, 2024 from https://www.earthquaketracker.org/earthquakes/event/us6000kvsp/