4.8

M4.8 Earthquake 153 km SW of Akhiok, AlaskaAugust 17, 2022

2022-08-17 02:00:18 UTC (2022-08-17) · approx. 4:00 PM UTC-10 local

MagnitudeM4.8(mww)
Time02:00 UTC4:00 PM UTC-10
Depth34.7 kmshallow crustal
Coordinates55.895°, -155.796°
Felt byNo felt reports
Status✓ Reviewed by USGS· Tsunami evaluation
Tsunami Warning Issued

On August 17, 2022 at 02:00 UTC, a magnitude 4.8 shallow crustal earthquake struck 153 km SW of Akhiok, Alaska, at a depth of 34.7 km and coordinates 55.8953°, -155.7956°.

Physical scale: An earthquake of magnitude 4.8 releases seismic energy equivalent to roughly 239 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.2 km — 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 55.90°, -155.80°

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 M4.8 earthquake near 153 km SW of Akhiok, Alaska

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

Earthquake Details

Magnitude
4.8 mww
Depth
34.7 km
shallow crustal
Location
55.8953°N
-155.7956°E
Intensity (MMI)
3.6
light

Technical Information

Event ID
ak022air9dp1
Event Type
earthquake
Status
✓ Reviewed
Significance
354
RMS Residual
0.65 sec
Last Updated
2022-10-28 02:26:37 UTC

Common Questions

How strong was the magnitude 4.8 earthquake near Akhiok, Alaska?

The magnitude 4.8 earthquake that struck 153 km SW of Akhiok, Alaska on August 17, 2022 at 02:00 UTC had a depth of 34.7 km. For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at 55.8953°, -155.7956°, which is 153 km SW of Akhiok, Alaska. View all earthquakes in Alaska.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.8 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 4.8 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: ak022air9dp1). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2022, August 17, 2022). M4.8 Earthquake 153 km SW of Akhiok, AlaskaAugust 17, 2022. Retrieved October 28, 2022 from https://www.earthquaketracker.org/earthquakes/event/ak022air9dp1/