4.0

M4.0 Earthquake 108 km S of Adak, AlaskaMarch 7, 2022

2022-03-07 17:55:38 UTC (2022-03-07) · approx. 5:55 AM UTC-12 local

MagnitudeM4.0(mb)
Time17:55 UTC5:55 AM UTC-12
Depth10.0 kmshallow crustal
Coordinates50.901°, -176.591°
Felt byNo felt reports
Status✓ Reviewed by USGS

On March 7, 2022 at 17:55 UTC, a magnitude 4.0 shallow crustal earthquake struck 108 km S of Adak, Alaska, at a depth of 10.0 km and coordinates 50.9005°, -176.5914°.0

Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 50.90°, -176.59°

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 M4.0 earthquake near 108 km S of Adak, Alaska

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

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from submitted citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.

USGS DYFI community-reported intensity map for the M4.0 earthquake near 108 km S of Adak, Alaska

Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report

Earthquake Details

Magnitude
4.0 mb
Depth
10.0 km
shallow crustal
Location
50.9005°N
-176.5914°E
Intensity (MMI)
1.8
weak
Community Intensity
1.0
CDI from reports

Technical Information

Event ID
us6000h2ur
Event Type
earthquake
Status
✓ Reviewed
Significance
246
Azimuthal Gap
144.0°
Min Station Distance
0.952°
RMS Residual
0.72 sec
Last Updated
2022-05-14 21:52:21 UTC

Common Questions

How strong was the magnitude 4.0 earthquake near Adak, Alaska?

The magnitude 4.0 earthquake that struck 108 km S of Adak, Alaska on March 7, 2022 at 17:55 UTC had a depth of 10.0 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 4.0 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 4.0 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us6000h2ur). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2022, March 7, 2022). M4.0 Earthquake 108 km S of Adak, AlaskaMarch 7, 2022. Retrieved May 14, 2022 from https://www.earthquaketracker.org/earthquakes/event/us6000h2ur/