M4.7 Earthquake 83 km SSW of Unalaska, Alaska — October 11, 2022
2022-10-11 22:07:33 UTC (2022-10-11) · approx. 11:07 AM UTC-11 local
On October 11, 2022 at 22:07 UTC, a magnitude 4.7 shallow crustal earthquake struck 83 km SSW of Unalaska, Alaska, at a depth of 44.2 km and coordinates 53.1584°, -166.8917°. This earthquake was detected by 75 seismic stations with good location accuracy and was assigned a USGS significance rating of 340, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.7 releases seismic energy equivalent to roughly 169 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.1 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
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Earthquake Details
-166.8917°E
Technical Information
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Common Questions
How strong was the magnitude 4.7 earthquake near Unalaska, Alaska?
The magnitude 4.7 earthquake that struck 83 km SSW of Unalaska, Alaska on October 11, 2022 at 22:07 UTC had a depth of 44.2 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 53.1584°, -166.8917°, which is 83 km SSW of Unalaska, Alaska. View all earthquakes in Alaska.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.7 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 4.7 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us6000isur). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2022, October 11, 2022). M4.7 Earthquake 83 km SSW of Unalaska, Alaska — October 11, 2022. Retrieved December 17, 2022 from https://www.earthquaketracker.org/earthquakes/event/us6000isur/