Thursday 30 January 2020

Magnitude 7.7 Earthquake between Cuba and Jamaica.

The United States Geological Survey recorded a Magnitude 7.7 Earthquake at a depth of 10 km roughly half way between the islands of Cuba and Jamaica in the Greater Antilles, at about 2.10 pm local time (about 7.10 pm GMT) on Tuesday 28 January 2020. Remarkably there are no reports of any damage or injuries associated with this event, however people have reported felling it across Jamaica, Cuba, the Cayman Islands, Haiti, Peurto Rica, Florida and western Mexico.

The approximate location of the 28 January 2020 Greater Antilles Earthquake. USGS.

Cuba lies on the southern portion of the North American Plate, to the north of the Septentrional Fault Zone, which forms the boundary with the Gonâve Microplate, a small tectonic plate underlying northern Jamaica and most of the island of Hispaniola. The Gonâve Microplate is moving east relative to the North American Plate, pushed by the Mid-Cayman Spreading centre to the west of Jamaica.

To the south the Gonâve Microplate is separated from the Caribbean Plate by the Enriquilo-Plantain Garden Fault Zone, which runs across Southern Haiti and the Dominican Republic. To the west the fault runs through central Jamaica. The Caribbean Plate is rotating clockwise, effectively moving east relative to the Gonâve Microplate.

Plate movements and fault zones around the Gonâve Microplate. Mike Norton/Wikimedia Commons.

None of these movements are smooth, with rock formations at the boundaries of the plates constantly sticking together then breaking apart as the pressure from the plate movement builds up, triggering Earthquakes in the process.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

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