3.5

M3.5 Earthquake 230 km ESE of Attu Station, AlaskaJuly 19, 2026

2026-07-19 21:39:23 UTC (5 days ago) · approx. 9:39 AM UTC+12 local

MagnitudeM3.5(ml)
Time21:39 UTC9:39 AM UTC+12
Depth17.6 kmshallow crustal
Coordinates51.948°, 176.241°
Felt byNo felt reports
Status✓ Reviewed by USGS

On July 19, 2026 at 21:39 UTC, a magnitude 3.5 shallow crustal earthquake struck 230 km ESE of Attu Station, Alaska, at a depth of 17.6 km and coordinates 51.9480°, 176.2410°.

Physical scale: An earthquake of magnitude 3.5 releases seismic energy equivalent to roughly 2.7 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 157 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 51.95°, 176.24°

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 M3.5 earthquake near 230 km ESE of Attu Station, Alaska

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

Earthquake Details

Magnitude
3.5 ml
Depth
17.6 km
shallow crustal
Location
51.9480°N
176.2410°E
Intensity (MMI)
1.3
weak

Technical Information

Event ID
aka2026offrzs
Event Type
earthquake
Status
✓ Reviewed
Significance
188
Stations Used
13
Azimuthal Gap
196.0°
Min Station Distance
1.400°
RMS Residual
0.80 sec
Last Updated
2026-07-24 19:34:59 UTC

Common Questions

How strong was the magnitude 3.5 earthquake near Attu Station, Alaska?

The magnitude 3.5 earthquake that struck 230 km ESE of Attu Station, Alaska on July 19, 2026 at 21:39 UTC had a depth of 17.6 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 3.5 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.5 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: aka2026offrzs). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2026, July 19, 2026). M3.5 Earthquake 230 km ESE of Attu Station, AlaskaJuly 19, 2026. Retrieved July 24, 2026 from https://www.earthquaketracker.org/earthquakes/event/aka2026offrzs/