Catalog of felt earthquakes for Puerto Rico and neighboring islands 1493-1899 with additional information for some 20th century earthquakes

Abstract

Numerous significant earthquakes have affected Puerto Rico and the U.S. Virgin Islands in the last 500 years. Written records from Colonial archives in Europe, as well as local and regional newspaper and government reports provide eyewitness data substantiating more than 200 felt events between the beginning of written re- cords in 1493 and 1899. Destructive earthquakes with clearly identified aftershock sequences occurred in 1670, 1787, 1867, and 1918 in Puerto Rico. Other significant events occurred in 1844, 1846, 1875, 1906, and 1943. 

The use of eyewitness reports is a powerful tool that can be used to restrict entry of only certified events into a catalog of felt earthquakes. Lack of eyewit- ness reports helped develop a list of suspicious or non-existent events. It also leads to the notation in the catalog of non-existent major earthquakes in 1717 and 1824 (2 events). The 1717 event, first reported in 1924, came into existence by an apparent typographical error, as other information in the same report only makes sense if the event referred to occurs in 1787. The other events, originally reported for St. Thomas in the Virgin Islands, apparently occurred in St. Thomas Parish, Jamaica. 

Some authors have assumed that earthquakes have occurred or embellished reports; other events have erroneous dates and/or places. One of these cases is the reference to a non-existent aftershock of the great earthquake of 1787. The only source for the seismic and “related events” notes them to all have occurred on May 10th, in Ponce, when in fact they occurred in different places and on different dates. 

This catalog of felt events, 1493-1899, and list of suspicious or non-existent events, while designed to serve as a basis for future catalogs and investigations, does not present a complete picture for the stronger shocks as complete catalogs from neighboring islands, useful to constrain their size and location, are lack- ing.