The 1918 San Fermín earthquake, also known as the Puerto Rico earthquake of 1918, struck the island of

Puerto Rico ; abbreviated PR), officially the Commonwealth of Puerto Rico, is a Government of Puerto Rico, self-governing Caribbean Geography of Puerto Rico, archipelago and island organized as an Territories of the United States, unincorporated territo ...

at on October 11. The earthquake measured 7.1 on the

moment magnitude scale The moment magnitude scale (MMS; denoted explicitly with or Mwg, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. was defined in a 1979 paper ...

and IX (''Violent'') on the

Mercalli intensity scale The Modified Mercalli intensity scale (MM, MMI, or MCS) measures the effects of an earthquake at a given location. This is in contrast with the seismic magnitude usually reported for an earthquake. Magnitude scales measure the inherent force or ...

. The mainshock

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. Determination The primary purpose of a ...

occurred off the northwestern coast of the island, somewhere along the

Puerto Rico Trench The Puerto Rico Trench is located on the boundary between the North Atlantic Ocean and Caribbean Sea, parallel to and north of Puerto Rico, where the oceanic trench reaches the deepest points in the Atlantic Ocean. The trench is associated with ...

. The earthquake triggered a

tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...

that swept the west coast of the island. The combined effects of the earthquake and tsunami made it one of the worst natural disasters that have struck the island. The losses resulting from the disaster were approximately 76–118 casualties and $4–29 million in property damage.

Earthquake

The epicenter of the 1918 San Fermín earthquake was located in the

Mona Passage The Mona Passage () is a strait that separates the islands of Hispaniola and Puerto Rico. The Mona Passage connects the Atlantic Ocean to the Caribbean Sea and is an important shipping route between the Atlantic and the Panama Canal. The Mona Pas ...

off the northwestern coast of the island. The strongest ground shaking has been estimated at intensity IX on the

. The resulting tsunami affected primarily the west coast towns of the island, primarily

Aguadilla Aguadilla (, ), founded in 1775 by Luis de Córdova, is a city and municipality located in the northwestern tip of Puerto Rico, bordered by the Atlantic Ocean to the north and west, north of Aguada, and Moca and west of Isabela. Aguadilla is s ...

and Mayaguez.

Damage

Numerous structures in the west coast suffered irreparable damage. Factories and production facilities were virtually destroyed, while bridges and roads were severely damaged. The earthquake caused several mudslides in areas where the intensity exceeded Level VII, but none caused numerous deaths. River currents were also affected, which, in many cases affected the foundations of many bridges, resulted in their collapse. Telegraph cables under the ocean were damaged, cutting off the island from outside communication for a time. The reported

casualties A casualty (), as a term in military usage, is a person in military service, combatant or non-combatant, who becomes unavailable for duty due to any of several circumstances, including death, injury, illness, missing, capture or desertion. In c ...

of the earthquake have been estimated somewhere between 76 and 116 deaths. Approximately 40 of these deaths were caused by the tsunami which swept shore communities. Damage to property was estimated to be between $4 and 29 million. In

, the closest town to the earthquake epicenter, the

parish church A parish church (or parochial church) in Christianity is the Church (building), church which acts as the religious centre of a parish. In many parts of the world, especially in rural areas, the parish church may play a significant role in com ...

and most of the stone and concrete buildings were either destroyed or partially damaged. The nearby Spanish-built Punta Higuero lighthouse of Rincón was also severely damaged. In Mayagüez, the largest city to be directly affected, 700 masonry buildings were damaged and 1,000 wooden houses, leaving many people homeless. Major buildings like the

church Church may refer to: Religion * Church (building), a place/building for Christian religious activities and praying * Church (congregation), a local congregation of a Christian denomination * Church service, a formalized period of Christian comm ...

post office A post office is a public facility and a retailer that provides mail services, such as accepting letter (message), letters and parcel (package), parcels, providing post office boxes, and selling postage stamps, packaging, and stationery. Post o ...

, municipal theater and

city hall In local government, a city hall, town hall, civic centre (in the UK or Australia), guildhall, or municipal hall (in the Philippines) is the chief administrative building of a city, town, or other municipality. It usually houses the city o ...

were severely damaged. With fear of the aftershocks, many camped out in the hills for weeks.Peter Aviles, "The Earthquake of the Century"
2002, hosted at University of Puerto Rico, accessed 24 October 2013 Some of the buildings of the recently founded University of Puerto Rico campus were also damaged or destroyed. The Edificio José de Diego suffered structural damage and the Degetau Hall was destroyed with its main entrance portico being the only standing structure left intact. These ruins were later preserved, and its portico would later on become a local landmark and the official emblem of the institution today. The historic center of San Germán was also badly affected, with reported damage to notable structures such as the main town church. Cities throughout the southern coast were also affected. The United States Customs House was destroyed while the

Ponce city hall The Ponce City Hall () is a historic city hall in Ponce, Puerto Rico. It is located it the center of the city, on Federico Degetau, Calle Degetau, across from Plaza Degetau in the Ponce Historic Zone. The building serves as the seat of the execu ...

for example was damaged, prompting the mayoral office to temporarily relocated to the Parque de Bombas until 1920.Armando Morales-Pares, State Architect, and Abelardo Gonzalez-Architect, State Historic Preservation Office, 23 May 1984. In ''National Register of Historic Places Inventory-Nomination Form – Parque de Bombas de Ponce – (Ponce Firehouse)''. United States Department of the Interior. National Park Service. (Washington, D.C.) p. 3. Listing Reference Number 84003150. 12 July 1984. Other damaged buildings in Ponce were the Tricoche Hospital and the Armstrong-Poventud House.Mariano G. Coronas Castro, Certifying Official; Felix J. del Campo, State Historian; and Jorge Ortiz Colom, State Architect, Puerto Rico Historic Preservation Office. (San Juan, Puerto Rico) April 7, 1987. In ''National Register of Historic Places Inventory – Nomination Form''. United States Department of the Interior. National Park Service. (Washington, D.C.) p. 3. Listing Reference Number 87000769. May 14, 1986. with There was damage reported further afield throughout Puerto Rico, for example the original bell towers of the

cathedral A cathedral is a church (building), church that contains the of a bishop, thus serving as the central church of a diocese, Annual conferences within Methodism, conference, or episcopate. Churches with the function of "cathedral" are usually s ...

of Humacao and the main town church of Vega Baja also collapsed. The Corregimiento Plaza Theater, the

and the

Arecibo Arecibo (; ) is a Arecibo barrio-pueblo, city and Municipalities of Puerto Rico, municipality on the northern coast of Puerto Rico, on the shores of the Atlantic Ocean, located north of Utuado, Puerto Rico, Utuado and Ciales, Puerto Rico, Ciale ...

also sustained damage. with

Tsunami

As a result of the earthquake, a

lashed the west coast of the island, probably 4–7 minutes after the main shock. The highest waves were estimated at in Point Agujereada, at Punta Borinquen (where it destroyed the

lighthouse A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lens (optics), lenses and to serve as a beacon for navigational aid for maritime pilots at sea or on inland waterways. Ligh ...

), and at Point Jiguero. Several coastal villages were destroyed, and it has been estimated that 40 people drowned (32 in Aguadilla alone) as a direct result of the tsunami. The earthquake and consequent tsunami destroyed most historic vernacular residences in downtown Aguadilla with only a few, such as the Amparo Roldán residence, surviving. Many of the historic tombs and mausolea of the historic cemetery were also badly damaged by the waves. with

Aftershocks

Several

aftershock In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in Epicenter, the same area of the Mainshock, main shock, caused as the displaced Crust (geology), crust adjusts to the effects of the main shock. Large earthq ...

s were reported immediately after the main earthquake. On October 24 and November 12, two strong aftershocks (6.4 and 6.1 Mw, respectively) were reported on the island. However, no damage was reported as a result.

United States response

The response from the United States was to exempt the municipalities most affected from paying taxes for a short period immediately following the quake: those municipalities were Mayagüez, Aguada,

, Añasco and Isabela. The U.S. appropriated funds for the repair of municipal buildings of the most affected municipalities.

Gallery

File:Iglesia Mayaguez 1918.jpg, Cathedral of Mayagüez after the first earthquake; further damage toppled the left tower File:Terremoto-pr-2.gif, Destroyed brick homes in Mayagüez File:Epicenters of earthquakes around Puerto Rico in last 100 years.jpg, Map showing the epicenters of all the magnitude 5 and greater earthquakes around Puerto Rico for the last 100 years File:Aguadilla Punta Borinquen Lighthouse Ruins.jpg, Aguadilla Punta Borinquen Lighthouse Ruins – an 1889 lighthouse destroyed by the tsunami

References

Sources * * *

External links

"Puerto Rico Seismic Network"
– University of Puerto Rico, Mayaguez
Significant earthquake – Puerto Rico: Mona Passage
–

National Geophysical Data Center The United States National Geophysical Data Center (NGDC) provided scientific stewardship, products and services for geophysical data describing the solid earth, marine, and solar-terrestrial environment, as well as earth observations from spac ...

M 7.1 – Puerto Rico region
–

United States Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on Mar ...

The Tectonic Setting and Geology of Puerto Rico and Its Surrounding Seafloor
–

National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with Weather forecasting, forecasting weather, monitoring oceanic and atmospheric conditions, Hydrography, charting the seas, ...

Map of Tsunami wave heights in Puerto Rico by USC Tsunami Research Group

Wave transformation in Coastal Wiki

Earthquakes and Tsunamis in Puerto Rico and the U.S. Virgin Islands by USGS.gov
* {{DEFAULTSORT:1918 San Fermín earthquake Mayagüez, Puerto Rico San Fermin Earthquake, 1918 San Fermin Earthquake, 1918 1910s tsunamis Earthquakes in Puerto Rico