Sunday, 8 July 2012

Earthquake in the Dominican Republic.

On Saturday 7 July 2012, slightly after 4.30 pm local time (slightly after 8.30 pm GMT), an Earthquake occurred in the Dominican Republic close to the border with Haiti, about 3 km south of the town of Pescaderia, at a depth of 19.9 km, according to the United States Geological Survey, who measured the  quake as 5.1 on the Richter Scale. This is large enough and shallow enough to have the potential to cause problems for people living nearby, but there are no reports of any damage or casualties on this occasion.

Map of the island of Hispaniola showing the location of the 7 July 2012 Earthquake; the black line is the national border between Haiti to the west and the Dominican Republic to the east. The purple lines represent transform faults, where two tectonic plates are moving past one-another, and the green lines represent convergent plate margins, where one tectonic plate is being subducted beneath another. USGS.

The Island of Hispaniola, on which the Dominican Republic and Haiti sit, is on the collision zone between the Caribbean and North American Plates. The northernmost part of the island is located on the North American Plate, the middle of the island is on the Gonâve Microplate, and the southern part of the island on the Caribbean Plate. The 7 July Earthquake occurred on the boundary between the Gonâve Microplate and the Caribbean Plate, which is both a transform plate, with the plates moving past one another, and a subduction zone with the Caribbean Plate sinking beneath the Gonâve Microplate. This fault continues to the west, running through the center of Jamaica, and to the east, running to the south of Puerto Rica. On the North of the island a similar fault occurs where the North American Plate is being subducted beneath the Gonâve Microplate. This fault extends to the west along the south coast of Cuba, and east to the north of Puerto Rica. 

Map showing the boundaries between the Caribbean and neighboring plates. Hispaniola is north of the word 'Plate'. Purdue University

Tectonic plates do not move smoothly past one another, but continuously stick as the rocks adhere together then break apart when the pressure builds up. This makes the island of Hispaniola extremely prone to Earthquakes, some of which have been extremely destructive. In January 2010 a massive Earthquake in southern Haiti killed an estimated 316 000 people and made over a million homeless.


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