QQuakeFacts
QuakeFactsEvidence report · prepared 2 September 2026https://quakes99.com/entity/iscgem901750
USGS iscgem901750

28 Dec 1940, 17:37

Mariana Islands region

A magnitude 7.7 mw earthquake at 15 km depth.

Depth15 kmPublished hypocentral depth
Tsunami flagNot flaggedUSGS catalog flag, not a current warning
Updated26 April 2022Latest timestamp stored in this record

Published location

Where is Mariana Islands region?

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

18.204000, 147.462000

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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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Nearby events with a similar magnitude

M 7.7

Pagan region, Northern Mariana Islands

M 7.6

Volcano Islands, Japan region

M 7.5

Northern Mariana Islands

M 7.9

Volcano Islands, Japan region

M 7.5

Volcano Islands, Japan region

M 7.2

Mariana Islands region

Catalog fields and provenance
Event ID
iscgem901750
Coordinates
18.204, 147.462
Network
iscgem
Significance
912