4.0

M4.0 Earthquake 95 km SW of Atka, AlaskaDecember 27, 2025

2025-12-27 22:08:24 UTC (2025-12-27) · approx. 10:08 AM UTC-12 local

MagnitudeM4.0(mb)
Time22:08 UTC10:08 AM UTC-12
Depth45.3 kmshallow crustal
Coordinates51.594°, -175.197°
Felt byNo felt reports
Status✓ Reviewed by USGS

On December 27, 2025 at 22:08 UTC, a magnitude 4.0 shallow crustal earthquake struck 95 km SW of Atka, Alaska, at a depth of 45.3 km and coordinates 51.5937°, -175.1974°.

Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 51.59°, -175.20°

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 M4.0 earthquake near 95 km SW of Atka, Alaska

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

Earthquake Details

Magnitude
4.0 mb
Depth
45.3 km
shallow crustal
Location
51.5937°N
-175.1974°E
Intensity (MMI)
3.1
light

Technical Information

Event ID
us7000rl4l
Event Type
earthquake
Status
✓ Reviewed
Significance
246
Stations Used
57
Azimuthal Gap
212.0°
Min Station Distance
0.599°
RMS Residual
0.92 sec
Last Updated
2026-04-01 22:48:24 UTC

Common Questions

How strong was the magnitude 4.0 earthquake near Atka, Alaska?

The magnitude 4.0 earthquake that struck 95 km SW of Atka, Alaska on December 27, 2025 at 22:08 UTC had a depth of 45.3 km. For context, this was a light earthquake commonly felt near the epicenter.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.0 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: us7000rl4l). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2025, December 27, 2025). M4.0 Earthquake 95 km SW of Atka, AlaskaDecember 27, 2025. Retrieved May 23, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000rl4l/