The 1787 Boricua earthquake struck offshore of the island of

Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and unincorporated ...

on May 2. The

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

of the earthquake was believed to have been around 8.0–8.5, however there is evidence that it was only about 6.9. The

epicenter The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental pe ...

is thought to have been somewhere north of Puerto Rico, probably on the

Puerto Rico Trench The Puerto Rico Trench is located on the boundary between the Caribbean Sea and the Atlantic Ocean. The oceanic trench, the deepest in the Atlantic, is associated with a complex transition between the Lesser Antilles subduction zone to the sou ...

.Earthquake History of Puerto Rico and the Virgin Islands
on

USGS The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, a ...

Puerto Rican

geomorphologist Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or ...

José Molinelli considers it "the strongest" in the seismic history of the country.

Effects

According to some sources, the earthquake was felt all across the Island. It demolished some structures like the

Arecibo Arecibo (; ) is a city and municipality on the northern coast of Puerto Rico, on the shores of the Atlantic Ocean, located north of Utuado and Ciales; east of Hatillo; and west of Barceloneta and Florida. It is about west of San Juan, th ...

church, along with monasteries like El Rosario and La Concepcion. It is also reported that it damaged the churches at Bayamon,

Toa Baja Toa Baja (, ) is a town and municipality of Puerto Rico located in the northern coast, north of Toa Alta and Bayamón; east of Dorado; and west of Cataño. Toa Baja is spread over five barrios, including Toa Baja Pueblo (the downtown area and ...

and Mayagüez. It also caused considerable damage to the forts of San Felipe del Morro and San Cristobal, breaking cisterns, walls and guard houses. Apparently, the earthquake did not cause major damage in the South of the island, but did crack the walls of the Our Lady of Guadalupe church in Ponce.''Historia sísmica de Puerto Rico: Terremotos significativos en la zona de Puerto Rico.''
SalonHogar.com Accessed 22 March 2018. There are no historical records of damage to the surrounding islands, adding to the evidence that the quake was smaller than previously thought.

Evidence

The earthquake that struck the island has little historical record itself, but some of the little evidence that exists suggests that effects were done to the topography of the

ocean floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

. Also, soil deposits give evidence that the event may have had a physical effect on the island; this evidence suggests that the island may have sunk about 3 meters. It is estimated that the tsunami produced by the earthquake may have been some 40–60 ft high, mostly because the Caribbean ocean in particular is quite shallow. Coastal regions of the island were swamped, producing a thin layer of the crust, showing that salt water had reached almost 2 miles inland.

References

External links

Historia sísmica de Puerto Rico
{{DEFAULTSORT:1787 Puerto Rico Earthquake Boricua Earthquake, 1787 Boricua Earthquake, 1787 18th century in Puerto Rico Earthquakes in Puerto Rico Megathrust earthquakes 1787 in Puerto Rico

Effects

Evidence

See also

References

External links