4.6

M4.6 Earthquake 320 km WSW of Adak, AlaskaApril 12, 2022

2022-04-12 17:54:55 UTC (2022-04-12) · approx. 5:54 AM UTC+12 local

MagnitudeM4.6(mb)
Time17:54 UTC5:54 AM UTC+12
Depth49.8 kmshallow crustal
Coordinates51.297°, 178.882°
Felt byNo felt reports
Status✓ Reviewed by USGS

On April 12, 2022 at 17:54 UTC, a magnitude 4.6 shallow crustal earthquake struck 320 km WSW of Adak, Alaska, at a depth of 49.8 km and coordinates 51.2965°, 178.8816°.

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 51.30°, 178.88°

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 320 km WSW of Adak, Alaska

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

Earthquake Details

Magnitude
4.6 mb
Depth
49.8 km
shallow crustal
Location
51.2965°N
178.8816°E
Intensity (MMI)
2.9
weak

Technical Information

Event ID
us7000h1ia
Event Type
earthquake
Status
✓ Reviewed
Significance
326
Azimuthal Gap
134.0°
Min Station Distance
0.276°
RMS Residual
0.83 sec
Last Updated
2022-06-20 22:07:58 UTC

Common Questions

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

The magnitude 4.6 earthquake that struck 320 km WSW of Adak, Alaska on April 12, 2022 at 17:54 UTC had a depth of 49.8 km. For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at 51.2965°, 178.8816°, which is 320 km WSW of Adak, 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: us7000h1ia). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2022, April 12, 2022). M4.6 Earthquake 320 km WSW of Adak, AlaskaApril 12, 2022. Retrieved June 20, 2022 from https://www.earthquaketracker.org/earthquakes/event/us7000h1ia/