M3.8 Earthquake 113 km SW of Nikolski, Alaska — January 26, 2021
2021-01-26 23:35:59 UTC (2021-01-26) · approx. 12:35 PM UTC-11 local
On January 26, 2021 at 23:35 UTC, a magnitude 3.8 shallow crustal earthquake struck 113 km SW of Nikolski, Alaska, at a depth of 49.4 km and coordinates 52.2967°, -170.1542°.
Physical scale: An earthquake of magnitude 3.8 releases seismic energy equivalent to roughly 7.6 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 252 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 5.0 mainshock that occurred 28 days ago 92 km SSW of Nikolski, Alaska. Since the mainshock, the USGS has recorded 70 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
-170.1542°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.8 earthquake near Nikolski, Alaska?
The magnitude 3.8 earthquake that struck 113 km SW of Nikolski, Alaska on January 26, 2021 at 23:35 UTC had a depth of 49.4 km. For context, this was a minor earthquake typically detected only by instruments.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.8 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.0 one earlier?
No. This magnitude 3.8 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier 92 km SSW of Nikolski, Alaska. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 3.8 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us6000de7l). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, January 26, 2021). M3.8 Earthquake 113 km SW of Nikolski, Alaska — January 26, 2021. Retrieved April 13, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000de7l/