M4.2 Earthquake 106 km ESE of Petropavlovsk-Kamchatsky, Russia — September 21, 2025
2025-09-21 23:28:57 UTC (2025-09-21) · approx. 10:28 AM UTC+11 local
On September 21, 2025 at 23:28 UTC, a magnitude 4.2 shallow crustal earthquake struck 106 km ESE of Petropavlovsk-Kamchatsky, Russia, at a depth of 35.0 km and coordinates 52.6449°, 160.0520°.
Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 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 5.8 mainshock that occurred 16 days ago 72 km E of Petropavlovsk-Kamchatsky, Russia. Since the mainshock, the USGS has recorded 1 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
160.0520°E
Technical Information
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Common Questions
How strong was the magnitude 4.2 earthquake near Petropavlovsk-Kamchatsky, Russia?
The magnitude 4.2 earthquake that struck 106 km ESE of Petropavlovsk-Kamchatsky, Russia on September 21, 2025 at 23:28 UTC had a depth of 35.0 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 4.2 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.8 one earlier?
No. This magnitude 4.2 earthquake is an aftershock of the larger magnitude 5.8 mainshock that occurred earlier 72 km E of Petropavlovsk-Kamchatsky, Russia. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 4.2 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000rh4d). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, September 21, 2025). M4.2 Earthquake 106 km ESE of Petropavlovsk-Kamchatsky, Russia — September 21, 2025. Retrieved December 6, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000rh4d/