4.0

M4.0 Earthquake 229 km ESE of Attu Station, AlaskaJuly 1, 2026

2026-07-01 10:50:19 UTC (10 hours ago) · approx. 10:50 PM UTC+12 local

MagnitudeM4.0(ml)
Time10:50 UTC10:50 PM UTC+12
Depth20.4 kmshallow crustal
Coordinates52.298°, 176.450°
Felt byNo felt reports
Status✓ Reviewed by USGS

On July 1, 2026 at 10:50 UTC, a magnitude 4.0 shallow crustal earthquake struck 229 km ESE of Attu Station, Alaska, at a depth of 20.4 km and coordinates 52.2980°, 176.4500°.

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 52.30°, 176.45°

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 229 km ESE of Attu Station, Alaska

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

Earthquake Details

Magnitude
4.0 ml
Depth
20.4 km
shallow crustal
Location
52.2980°N
176.4500°E
Intensity (MMI)
2.5
weak

Technical Information

Event ID
aka2026mxdqsl
Event Type
earthquake
Status
✓ Reviewed
Significance
246
Stations Used
16
Azimuthal Gap
171.0°
Min Station Distance
1.300°
RMS Residual
0.80 sec
Last Updated
2026-07-01 20:53:25 UTC

Common Questions

How strong was the magnitude 4.0 earthquake near Attu Station, Alaska?

The magnitude 4.0 earthquake that struck 229 km ESE of Attu Station, Alaska on July 1, 2026 at 10:50 UTC had a depth of 20.4 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: aka2026mxdqsl). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2026, July 1, 2026). M4.0 Earthquake 229 km ESE of Attu Station, AlaskaJuly 1, 2026. Retrieved July 1, 2026 from https://www.earthquaketracker.org/earthquakes/event/aka2026mxdqsl/