M 7.7 earthquake – 45 km N of San Antonio, Puerto Rico

Jul 29, 1943 · 03:02 UTC · Jul 29, 1943
Local time: Jul 29, 1943 · 00:02 (UTC-3)

MajorShallow · 15 km Reviewed by a seismologist

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Magnitude: 7.7moment magnitude (mw)
Depth: 15 kmShallow earthquake
Epicenter: 18.907, -67.11854 km from Aguadilla
Energy released: 5.4 megatons of TNTabout 357 × Hiroshima
Felt reports: —"Did You Feel It?" responses
Shaking intensity: 6.5max. instrumental (MMI)
Aftershocks: 2M2.5+ within 190 km, up to 60 days
Significance: 912USGS score, 0–1,000+

The strongest within 300 km on record

No earthquake this strong has been recorded this close since our catalog begins in 1900.

How strong was it?

Major earthquake. It released 5.4 megatons of TNT, 11,220 times the energy of a magnitude 5.0. Bars use the magnitude scale: every step is about 32 times more energy.

Chile 1960 M 9.5

Japan 2011 M 9.1

San Francisco 1906 M 7.9

Turkey 2023 M 7.8

This earthquake M 7.7

Haiti 2010 M 7.0

Northridge 1994 M 6.7

Aftershocks

2 earthquakes of M2.5+ within 190 km in the 60 days after.

The strongest earthquakes within 300 km

Since 1900, around Puerto Rico.