QQuakeFacts
QuakeFactsEvidence report · prepared 2 September 2026https://quakes99.com/entity/official19250628012105000
USGS official19250628012105000

28 Jun 1925, 02:21

The 1925 Clarkston Valley, Montana Earthquake

A magnitude 6.6 mw earthquake at 0 km depth.

Depth0 kmPublished hypocentral depth
Tsunami flagNot flaggedUSGS catalog flag, not a current warning
Updated27 June 2025Latest timestamp stored in this record

Published location

Where is The 1925 Clarkston Valley, Montana Earthquake?

This locator uses the coordinates in the approved source record. It shows geographic context, not a site boundary, safety zone or property-risk area.

46.080000, -111.510000

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Map data © OpenStreetMap contributors

What the numbers mean

Magnitude measures event size; depth locates the source below the surface. Neither value alone establishes local damage or personal risk.

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Continue exploring

Nearby events with a similar magnitude

M 6.4

Clarkston Valley, Montana (Aftershock)

M 6.3

22 km SW of Mammoth, Wyoming

M 6.13

12 km N of Winston, Montana

M 6.1

30 km SSW of Big Sky, Montana

M 7.2

The 1959 Hebgen Lake, Montana Earthquake

M 5.3

29 km WSW of Freedom, Idaho

Catalog fields and provenance
Event ID
official19250628012105000
Coordinates
46.08, -111.51
Network
official
Significance
670