Alaska earthquakes

M5.1 earthquake 144 km WSW of Adak, Alaska

A magnitude 5.1 earthquake struck 144 km WSW of Adak, Alaska on Fri, Jul 4, 1997, 2:04 AM HADT (11:04 UTC), 33 km (21 mi) below the surface.

A larger quake followed: M5.9 146 km WSW of Adak, Alaska. This one was a foreshock.

Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 5.1 (Mwc, centroid moment), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Fri, Jul 4, 1997, 2:04 AM HADT
UTC: 1997-07-04 11:04:02 UTC
Depth: 33.0 km (20.5 mi), shallow
Epicenter: 51.417° N, 178.582° W
Region: Alaska
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
5.1	Mwc, centroid moment	USGS National Earthquake Information Center	Preferred · Reviewed
5.11	Mw, moment	ISC-GEM global catalog	Final · ±0.1

What happened

The USGS’s account of the effects of this earthquake.

Felt on Adak.

From the USGS event page for usp00084be. U.S. Geological Survey text and figures are in the public domain.

Did you feel it?

No one has reported feeling this quake to the USGS.

Fault motion and ground failure

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Faulting: Oblique reverse
Nodal plane 1: Strike 270°, dip 30°, rake 136°
Nodal plane 2: Strike 41°, dip 69°, rake 67°

How well it is located

Reviewed by a seismologist.

Depth from: OPERATOR_ASSIGNED

Nearby

Within 100 km, magnitude 2.1 and up: 14 in the 60 days after this one and 7 in the 30 days before it.

After

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp00084be (also filed as gcmt19970704110402, iscgem1035317). Read Fri, Oct 2, 2026, 11:18 AM UTC.