3.8

M3.8 Earthquake 82 km S of Unalaska, AlaskaFebruary 4, 2022

2022-02-04 16:23:41 UTC (2022-02-04) · approx. 5:23 AM UTC-11 local

MagnitudeM3.8(mb)
Time16:23 UTC5:23 AM UTC-11
Depth35.0 kmshallow crustal
Coordinates53.142°, -166.749°
Felt byNo felt reports
Status✓ Reviewed by USGS

On February 4, 2022 at 16:23 UTC, a magnitude 3.8 shallow crustal earthquake struck 82 km S of Unalaska, Alaska, at a depth of 35.0 km and coordinates 53.1418°, -166.7492°.

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.

Map showing earthquake epicenter at 53.14°, -166.75°

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 M3.8 earthquake near 82 km S of Unalaska, Alaska

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

Earthquake Details

Magnitude
3.8 mb
Depth
35.0 km
shallow crustal
Location
53.1418°N
-166.7492°E
Intensity (MMI)
2.0
weak

Technical Information

Event ID
us7000gi0q
Event Type
earthquake
Status
✓ Reviewed
Significance
222
Azimuthal Gap
170.0°
Min Station Distance
0.657°
RMS Residual
0.62 sec
Last Updated
2022-04-15 17:57:23 UTC

Common Questions

How strong was the magnitude 3.8 earthquake near Unalaska, Alaska?

The magnitude 3.8 earthquake that struck 82 km S of Unalaska, Alaska on February 4, 2022 at 16:23 UTC had a depth of 35.0 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.

Understanding This Data

Magnitude 3.8 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000gi0q). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2022, February 4, 2022). M3.8 Earthquake 82 km S of Unalaska, AlaskaFebruary 4, 2022. Retrieved April 15, 2022 from https://www.earthquaketracker.org/earthquakes/event/us7000gi0q/