3.9

M3.9 Earthquake 60 km SE of Adak, AlaskaMarch 23, 2022

2022-03-23 19:37:49 UTC (2022-03-23) · approx. 7:37 AM UTC-12 local

MagnitudeM3.9(mb)
Time19:37 UTC7:37 AM UTC-12
Depth45.7 kmshallow crustal
Coordinates51.469°, -176.048°
Felt byNo felt reports
Status✓ Reviewed by USGS

On March 23, 2022 at 19:37 UTC, a magnitude 3.9 shallow crustal earthquake struck 60 km SE of Adak, Alaska, at a depth of 45.7 km and coordinates 51.4690°, -176.0480°.

Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 11 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 296 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 51.47°, -176.05°

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 M3.9 earthquake near 60 km SE of Adak, Alaska

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

Earthquake Details

Magnitude
3.9 mb
Depth
45.7 km
shallow crustal
Location
51.4690°N
-176.0480°E
Intensity (MMI)
1.8
weak

Technical Information

Event ID
us7000gy45
Event Type
earthquake
Status
✓ Reviewed
Significance
234
Azimuthal Gap
141.0°
Min Station Distance
0.451°
RMS Residual
1.00 sec
Last Updated
2022-05-28 18:35:41 UTC

Common Questions

How strong was the magnitude 3.9 earthquake near Adak, Alaska?

The magnitude 3.9 earthquake that struck 60 km SE of Adak, Alaska on March 23, 2022 at 19:37 UTC had a depth of 45.7 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 3.9 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.9 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000gy45). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2022, March 23, 2022). M3.9 Earthquake 60 km SE of Adak, AlaskaMarch 23, 2022. Retrieved May 28, 2022 from https://www.earthquaketracker.org/earthquakes/event/us7000gy45/