Significant earthquakes of 1943

July 29, 1943 Earthquake: San Juan, Puerto Rico, US Territories

July 29, 1943 · M7.7

A magnitude 7.7 earthquake struck San Juan, Puerto Rico, US Territories on July 29, 1943 at 03:02:17 UTC, 15 km below the surface.

Map

Where it struck, with the other significant earthquakes within 200 km. Circles are sized and colored by magnitude; select one for its page.

The earthquake

Date
July 29, 1943
Time
03:02:17 UTC
Place
San Juan, Puerto Rico, US Territories
Magnitude
7.7 (Mw)
Magnitude scales
Mw 7.7 · Unspecified 7.8
Focal depth
15 km (9 mi)
Tsunami
None recorded
Epicenter
18.907° N, 67.118° W
Region
Caribbean

Mw: moment magnitude, based on the slip on the fault and the area that slipped. Unspecified: the method was not stated in the published sources. NCEI’s headline magnitude is the best of these for the earthquake.

The toll

The record gives no deaths, injuries or damage for this earthquake.

From Wikipedia

The 1943 Puerto Rico earthquake struck off the northwestern coast of the island of Puerto Rico at approximately 23:02 AST on July 28, 1943 (03:02 UTC on July 29). The earthquake, measured at 7.7 on the moment magnitude scale (Mw) by the United States Geological Service (USGS), struck in or near the eastern slope of the Mona Canyon along the Puerto Rico Trench, approximately 44 kilometres (27 mi) north of Aguadilla and 57 kilometres (35 mi) northwest of Arecibo. A small tsunami was reported along the northwestern coast of Puerto Rico but no fatalities or significant damages were reported.

It was the largest earthquake to impact the area since the destructive 1918 event. Despite being the largest earthquake to directly impact Puerto Rico in the 20th century, it produced no fatalities due to the time and depth of the seismic movement. Only minor injuries and moderate infrastructure damages totaling up to US$2 million were reported as a result.

Text from Wikipedia, “1943 Puerto Rico earthquake”, licensed CC BY-SA 4.0. Quoted as written; the full article has the rest.

What the record says

NCEI’s account, from the sources it cites.

1943-07-29, 03:02:17.21 UTC, 18.907 N 67.118 W, magnitude 7.7 Mw (reference #10476, v.10)

1943-07-29, 03:02:16 UTC, 19.25 N 67.5 W, magnitude 7.6 Mw (reference #9910)

1943, July 28th 2302 and 1943, July 29th 2102. Although this earthquake was of significant magnitude (7.5Mw), there was no damge anywhere on the island of Puerto Rico (reference #14050)

Sources NCEI cites

The publications NCEI lists for this record. The numbers match the “reference #” notes in its account above.

  1. #1189 Campbell, J.B. (1972). Earthquake History of Puerto Rico, Appendix I, Part A, Aguirre Nuclear Power Plant PSAR, Weston Geophysical Research, Inc., Weston, MA, 117 p.
  2. #10476 International Seismological Centre (2013). Final Scientific Report of the ISC-GEM Instrumental Earthquake Catalogue, ISC-GEM Global Instrumental earthquake Catalogue (1900-2021). Versions 1-12 downloaded beginning 18 March 2013. DOI: 10.31905/D808B825
  3. #9910 Engdahl, E.R., R. van der Hilst, R. Buland (2012). Centennial Earthquake Catalog. Retrieved August 11, 2011 from link
  4. #45 U.S. Department of the Interior, Geological Survey and U.S. Department of Commerce, National Oceanic and Atmospheric Administration (1928-1986). United States Earthquakes, Annual publication, published 1928-1986. vol.s for 1928-1965 issued by the U.S. Coast and Geodetic Survey; volumes for 1966-1969 issued by the National Earthquake Information Center; volume for 1970 issued by the National Geophysical Data Center; volumes for 1971-1972 issued by the National Geophysical And Solar-Terrestrial Data Center; volumes for 1973-1980 published jointly by the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey; volumes for 1981-1986 published by the U.S. Geological Survey. [on shelf]
  5. #14050 McCann, W., Feldman, L. and McCann, M. (2010). Catalog of felt earthquakes for Puerto Rico and neighboring islands 1493-1899 with additional information for some 20th century earthquakes. Revista Geofísica, (62), 141-220.

Other significant earthquakes nearby

Within 200 km, the deadliest first.

More

Significant earthquakes of 1943The 1900sEvery quake the USGS located in 1943Recent earthquakes near hereThis day in weather history

Sources

Significant earthquakes from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-10-01. NCEI earthquake 3751. The written accounts and the magnitude estimates are from the USGS earthquake catalog, event iscgem899944, matched to this record by time, place and magnitude.