M4.5 Earthquake 27 km WSW of Urakawa, Japan — April 30, 2023
2023-04-30 23:58:20 UTC (2023-04-30) · approx. 8:58 AM UTC+9 local
Aftershock of the M6.0 mainshock.
On April 30, 2023 at 23:58 UTC, a magnitude 4.5 shallow crustal earthquake struck 27 km WSW of Urakawa, Japan, at a depth of 68.4 km and coordinates 42.0642°, 142.4710°. This earthquake was detected by 67 seismic stations with good location accuracy and was assigned a USGS significance rating of 312, 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.
This earthquake is part of an ongoing aftershock sequence following the magnitude 6.0 mainshock that occurred 7 days ago 32 km SSW of Honchō, Japan. Since the mainshock, the USGS has recorded 0 aftershocks in this area. Aftershock activity is expected to continue for weeks to months as stresses on surrounding faults redistribute.
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
142.4710°E
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Common Questions
How strong was the magnitude 4.5 earthquake near Urakawa, Japan?
The magnitude 4.5 earthquake that struck 27 km WSW of Urakawa, Japan on April 30, 2023 at 23:58 UTC had a depth of 68.4 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 42.0642°, 142.4710°, which is 27 km WSW of Urakawa, 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.
Is this the same earthquake as the M6.0 one earlier?
No. This magnitude 4.5 earthquake is an aftershock of the larger magnitude 6.0 mainshock that occurred earlier 32 km SSW of Honchō, Japan. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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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Authoritative source: USGS event page (event ID: us7000jx9f). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, April 30, 2023). M4.5 Earthquake 27 km WSW of Urakawa, Japan — April 30, 2023. Retrieved July 15, 2023 from https://www.earthquaketracker.org/earthquakes/event/us7000jx9f/