4.6

M4.6 Earthquake 79 km S of Unalaska, AlaskaFebruary 2, 2022

2022-02-02 23:54:50 UTC (2022-02-02) · approx. 12:54 PM UTC-11 local

MagnitudeM4.6(mb)
Time23:54 UTC12:54 PM UTC-11
Depth35.0 kmshallow crustal
Coordinates53.171°, -166.696°
Felt byNo felt reports
Status✓ Reviewed by USGS

On February 2, 2022 at 23:54 UTC, a magnitude 4.6 shallow crustal earthquake struck 79 km S of Unalaska, Alaska, at a depth of 35.0 km and coordinates 53.1707°, -166.6957°.

Physical scale: An earthquake of magnitude 4.6 releases seismic energy equivalent to roughly 120 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 899 m — 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

Map showing earthquake epicenter at 53.17°, -166.70°

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.

USGS ShakeMap intensity contours for the M4.6 earthquake near 79 km S of Unalaska, Alaska

Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS

Earthquake Details

Magnitude
4.6 mb
Depth
35.0 km
shallow crustal
Location
53.1707°N
-166.6957°E
Intensity (MMI)
2.6
weak

Technical Information

Event ID
us7000ghgu
Event Type
earthquake
Status
✓ Reviewed
Significance
326
Azimuthal Gap
110.0°
Min Station Distance
0.633°
RMS Residual
0.96 sec
Last Updated
2022-04-15 17:57:14 UTC

Common Questions

How strong was the magnitude 4.6 earthquake near Unalaska, Alaska?

The magnitude 4.6 earthquake that struck 79 km S of Unalaska, Alaska on February 2, 2022 at 23:54 UTC had a depth of 35.0 km. For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at 53.1707°, -166.6957°, which is 79 km S of Unalaska, Alaska. View all earthquakes in Alaska.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.6 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 4.6 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: us7000ghgu). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2022, February 2, 2022). M4.6 Earthquake 79 km S of Unalaska, AlaskaFebruary 2, 2022. Retrieved April 15, 2022 from https://www.earthquaketracker.org/earthquakes/event/us7000ghgu/