M4.1 Earthquake 71 km SSW of Adak, Alaska — February 19, 2021
2021-02-19 15:33:08 UTC (2021-02-19) · approx. 3:33 AM UTC-12 local
On February 19, 2021 at 15:33 UTC, a magnitude 4.1 shallow crustal earthquake struck 71 km SSW of Adak, Alaska, at a depth of 35.0 km and coordinates 51.2517°, -176.8666°.
Physical scale: An earthquake of magnitude 4.1 releases seismic energy equivalent to roughly 21 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 406 m — a useful intuition for the size of the slip patch on the fault.
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 1 citizen response to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
-176.8666°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.1 earthquake near Adak, Alaska?
The magnitude 4.1 earthquake that struck 71 km SSW of Adak, Alaska on February 19, 2021 at 15:33 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 4.1 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.1 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000dixq). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, February 19, 2021). M4.1 Earthquake 71 km SSW of Adak, Alaska — February 19, 2021. Retrieved May 4, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000dixq/