4.0

M4.0 Earthquake 92 km SE of Atka, AlaskaJuly 25, 2026

2026-07-25 23:31:48 UTC (2026-07-25) · approx. 11:31 AM UTC-12 local

MagnitudeM4.0(mb)
Time23:31 UTC11:31 AM UTC-12
Depth41.2 kmshallow crustal
Coordinates51.539°, -173.368°
Felt byNo felt reports
Status✓ Reviewed by USGS

On July 25, 2026 at 23:31 UTC, a magnitude 4.0 shallow crustal earthquake struck 92 km SE of Atka, Alaska, at a depth of 41.2 km and coordinates 51.5387°, -173.3678°.

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 51.54°, -173.37°

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 92 km SE of Atka, Alaska

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

Earthquake Details

Magnitude
4.0 mb
Depth
41.2 km
shallow crustal
Location
51.5387°N
-173.3678°E
Intensity (MMI)
3.1
light

Technical Information

Event ID
us7000t3dn
Event Type
earthquake
Status
✓ Reviewed
Significance
246
Stations Used
57
Azimuthal Gap
185.0°
Min Station Distance
0.840°
RMS Residual
0.77 sec
Last Updated
2026-08-27 22:11:17 UTC

Common Questions

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

The magnitude 4.0 earthquake that struck 92 km SE of Atka, Alaska on July 25, 2026 at 23:31 UTC had a depth of 41.2 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.

Understanding This Data

Magnitude 4.0 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000t3dn). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2026, July 25, 2026). M4.0 Earthquake 92 km SE of Atka, AlaskaJuly 25, 2026. Retrieved August 27, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000t3dn/