3.1

M3.1 Earthquake south of AlaskaApril 28, 2023

2023-04-28 21:24:40 UTC (2023-04-28) · approx. 10:24 AM UTC-11 local

MagnitudeM3.1(ml)
Time21:24 UTC10:24 AM UTC-11
Depth9.3 kmshallow crustal
Coordinates54.738°, -157.870°
Felt byNo felt reports
Status✓ Reviewed by USGS

On April 28, 2023 at 21:24 UTC, a magnitude 3.1 shallow crustal earthquake struck south of Alaska, at a depth of 9.3 km and coordinates 54.7379°, -157.8701°.

Physical scale: An earthquake of magnitude 3.1 releases seismic energy equivalent to roughly 674 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 83 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 54.74°, -157.87°

Earthquake Details

Magnitude
3.1 ml
Depth
9.3 km
shallow crustal
Location
54.7379°N
-157.8701°E

Technical Information

Event ID
ak0235fi2a86
Event Type
earthquake
Status
✓ Reviewed
Significance
148
RMS Residual
0.46 sec
Last Updated
2023-07-11 01:44:58 UTC

Common Questions

How strong was the magnitude 3.1 earthquake south of Alaska?

The magnitude 3.1 earthquake that struck south of Alaska on April 28, 2023 at 21:24 UTC had a depth of 9.3 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 3.1 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.1 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: ak0235fi2a86). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, April 28, 2023). M3.1 Earthquake south of AlaskaApril 28, 2023. Retrieved July 11, 2023 from https://www.earthquaketracker.org/earthquakes/event/ak0235fi2a86/