3.7

M3.7 Earthquake 89 km E of Nikolski, AlaskaSeptember 30, 2025

2025-09-30 20:55:27 UTC (2025-09-30) · approx. 9:55 AM UTC-11 local

MagnitudeM3.7(mb)
Time20:55 UTC9:55 AM UTC-11
Depth81.7 kmintermediate depth
Coordinates53.030°, -167.544°
Felt byNo felt reports
Status✓ Reviewed by USGS

On September 30, 2025 at 20:55 UTC, a magnitude 3.7 intermediate depth earthquake struck 89 km E of Nikolski, Alaska, at a depth of 81.7 km and coordinates 53.0303°, -167.5445°.

Physical scale: An earthquake of magnitude 3.7 releases seismic energy equivalent to roughly 5.4 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 215 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 53.03°, -167.54°

Earthquake Details

Magnitude
3.7 mb
Depth
81.7 km
intermediate depth
Location
53.0303°N
-167.5445°E

Technical Information

Event ID
us6000rdx0
Event Type
earthquake
Status
✓ Reviewed
Significance
211
Stations Used
16
Azimuthal Gap
209.0°
Min Station Distance
0.440°
RMS Residual
1.17 sec
Last Updated
2025-12-11 21:40:37 UTC

Common Questions

How strong was the magnitude 3.7 earthquake near Nikolski, Alaska?

The magnitude 3.7 earthquake that struck 89 km E of Nikolski, Alaska on September 30, 2025 at 20:55 UTC had a depth of 81.7 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 3.7 earthquakes can continue for several days and gradually diminish over time.

What should I do after an earthquake?

If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.

Authoritative source: USGS event page (event ID: us6000rdx0). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2025, September 30, 2025). M3.7 Earthquake 89 km E of Nikolski, AlaskaSeptember 30, 2025. Retrieved May 28, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000rdx0/