The southern part of

Cuba Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...

was struck by a major earthquake on 12 June 1766 at midnight local time. It had an estimated magnitude of 6.8 and a maximum felt intensity of IX (''destructive'') on the MSK scale. Its epicenter was offshore, near Santiago de Cuba, with a focal depth of 25 km. Santiago de Cuba suffered the worse damage, although large areas of Cuba were affected. It was felt in both

Havana Havana (; Spanish: ''La Habana'' ) is the capital and largest city of Cuba. The heart of the La Habana Province, Havana is the country's main port and commercial center.

(800 km) and on

Jamaica Jamaica (; ) is an island country situated in the Caribbean Sea. Spanning in area, it is the third-largest island of the Greater Antilles and the Caribbean (after Cuba and Hispaniola). Jamaica lies about south of Cuba, and west of His ...

(140 km). Between 34 and 40 people died and a further 700 were injured.

Tectonic setting

The southernmost coast of Cuba lies adjacent to the southern margin of the

North American Plate The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...

. This boundary is a major left lateral (sinistral)

transform fault A transform fault or transform boundary, is a fault along a plate boundary where the motion is predominantly horizontal. It ends abruptly where it connects to another plate boundary, either another transform, a spreading ridge, or a subductio ...

, the Septentrional-Oriente fault zone, where the North American Plate is moving westwards relative to the

Gonâve Microplate Gonave may refer to: *Gulf of Gonâve *Gonâve Island *Gonâve Microplate See also *Gonaïves Gonaïves (; ht, Gonayiv, ) is a commune in northern Haiti, and the capital of the Artibonite department of Haiti. It has a population of about 300,00 ...

at a rate of between 6 and 11 mm per year. This fault zone forms the most seismically active part of Cuba.

Earthquake

The earthquake struck at midnight and lasted for between one and a half and seven minutes. From the observed seismic intensities, the epicenter is likely to have been offshore, although its precise location is unknown. The mainshock was followed by a series of

aftershock In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousand ...

s, that continued for a further 66 days. From its estimated location, it is interpreted to have been caused by rupture of the Septentrional-Oriente fault zone.

Damage

The intensity of shaking was at a maximum at

Morro Castle Morro Castle may refer to: Fortress * Morro Castle (Havana), a fortress guarding Havana Bay, Cuba * Castillo San Felipe del Morro, a fortress in San Juan, Puerto Rico * Castillo de San Pedro de la Roca The Castillo de San Pedro de la Roca (also k ...

and La Socapa Fort, with an estimated value of IX (''Destructive''), due to their proximity to the epicentre and the presence of thick alluvial deposits. Levels of VIII (''Damaging'') were reached in the cities of Santiago de Cuba and

Bayamo Bayamo is the capital city of the Granma Province of Cuba and one of the largest cities in the Oriente region. Overview The community of Bayamo lies on a plain by the Bayamo River. It is affected by the violent Bayamo wind. One of the most ...

. Morro Castle and La Socapa Fort were destroyed as were the hospital and the governor's house. Santiago de Cuba's cathedral was damaged. The earthquake is recorded to have caused the deaths of between 34 and 40 inhabitants, all of them in Santiago de Cuba. A further 700 people were injured.

References

{{Reflist 1760s earthquakes Earthquakes in Cuba 18th century in Cuba History of Santiago de Cuba Santiago de Cuba Province