5.1

M5.1 Earthquake near Rat Islands, Aleutian Islands, AlaskaNovember 5, 2023

2023-11-05 13:27:27 UTC (2023-11-05) · approx. 1:27 AM UTC+12 local

MagnitudeM5.1(mb)
Time13:27 UTC1:27 AM UTC+12
Depth70.4 kmintermediate depth
Coordinates51.395°, 178.347°
Felt byNo felt reports
Status✓ Reviewed by USGS· Tsunami evaluation
Tsunami Warning Issued

On November 5, 2023 at 13:27 UTC, a magnitude 5.1 intermediate depth earthquake struck near Rat Islands, Aleutian Islands, Alaska, at a depth of 70.4 km and coordinates 51.3952°, 178.3467°. This earthquake was detected by 95 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 400, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 5.1 releases seismic energy equivalent to roughly 674 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 2.0 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 51.40°, 178.35°

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 M5.1 earthquake near Rat Islands, Aleutian Islands, Alaska

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

Earthquake Details

Magnitude
5.1 mb
Depth
70.4 km
intermediate depth
Location
51.3952°N
178.3467°E
Intensity (MMI)
3.7
light

Technical Information

Event ID
us7000l90i
Event Type
earthquake
Status
✓ Reviewed
Significance
400
Stations Used
95
Azimuthal Gap
69.0°
Min Station Distance
0.555°
RMS Residual
0.67 sec
Last Updated
2025-10-21 01:08:13 UTC

Common Questions

How strong was the magnitude 5.1 earthquake near Rat Islands, Aleutian Islands, Alaska?

The magnitude 5.1 earthquake that struck near Rat Islands, Aleutian Islands, Alaska on November 5, 2023 at 13:27 UTC had a depth of 70.4 km. For context, this was a moderate earthquake that could be widely felt.

Where did the earthquake occur?

The earthquake epicenter was located at 51.3952°, 178.3467°, which is near Rat Islands, Aleutian Islands, Alaska. View all earthquakes in Alaska.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.1 earthquakes can continue for days to weeks 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 5.1 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: us7000l90i). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, November 5, 2023). M5.1 Earthquake near Rat Islands, Aleutian Islands, AlaskaNovember 5, 2023. Retrieved October 21, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000l90i/