M4.3 Earthquake 50 km ESE of Onagawa Chō, Japan — August 21, 2023
2023-08-21 17:41:34 UTC (2023-08-21) · approx. 2:41 AM UTC+9 local
On August 21, 2023 at 17:41 UTC, a magnitude 4.3 shallow crustal earthquake struck 50 km ESE of Onagawa Chō, Japan, at a depth of 51.4 km and coordinates 38.2644°, 141.9755°.
Physical scale: An earthquake of magnitude 4.3 releases seismic energy equivalent to roughly 43 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 558 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
141.9755°E
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Common Questions
How strong was the magnitude 4.3 earthquake near Onagawa Chō, Japan?
The magnitude 4.3 earthquake that struck 50 km ESE of Onagawa Chō, Japan on August 21, 2023 at 17:41 UTC had a depth of 51.4 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.3 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.3 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000kpxs). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, August 21, 2023). M4.3 Earthquake 50 km ESE of Onagawa Chō, Japan — August 21, 2023. Retrieved October 28, 2023 from https://www.earthquaketracker.org/earthquakes/event/us7000kpxs/