M4.9 Earthquake 91 km S of Atka, Alaska — January 14, 2021
2021-01-14 05:13:47 UTC (2021-01-14) · approx. 5:13 PM UTC-12 local
On January 14, 2021 at 05:13 UTC, a magnitude 4.9 shallow crustal earthquake struck 91 km S of Atka, Alaska, at a depth of 19.3 km and coordinates 51.3828°, -174.0614°.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 km — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in Alaska, a region characterized by Pacific Plate subduction beneath the North American Plate, producing frequent megathrust and crustal earthquakes along the Aleutian arc. The nearest mapped fault system is the Aleutian megathrust. View all earthquakes in Alaska.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
-174.0614°E
Technical Information
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Common Questions
How strong was the magnitude 4.9 earthquake near Atka, Alaska?
The magnitude 4.9 earthquake that struck 91 km S of Atka, Alaska on January 14, 2021 at 05:13 UTC had a depth of 19.3 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 51.3828°, -174.0614°, which is 91 km S of Atka, Alaska. View all earthquakes in Alaska.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 earthquakes can continue for several days and gradually diminish over time.
Has Alaska had earthquakes this big before?
The largest recorded earthquake in Alaska was the M9.2 Great Alaska earthquake of March 27, 1964. Today's magnitude 4.9 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us6000d87l). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, January 14, 2021). M4.9 Earthquake 91 km S of Atka, Alaska — January 14, 2021. Retrieved December 30, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000d87l/