The United States Geological Survey recorded a Magnitude 6.0 Earthquake at a depth of 18 km, off the coast of northwest Costa Rica slightly before 6.30 am (slightly before 12.30 pm) on Thursday 5 September 2013. This is a large quake, with the potential to be quite dangerous, but on this occasion no damage or casualties have been reported. The quake was felt as far away as the capital, San José, in the central part of the country.
The approximate location of the 5 September 2013 Costa Rica Earthquake. Google Maps.
Costa Rica lies on the southern margin of the Caribbean Plate; to the south of the country the Cocos Plate, which underlies part of the eastern Pacific Ocean) is being subducted under the Middle American Trench, passing under Central America as it sinks into the Earth's interior. This is not a smooth process, and the plates often stick together until the pressure builds up enough to force them to shift suddenly, causing Earthquakes. As the Cocos Plate sinks deeper if is partially melted by the friction and the heat of the Earth's interior. Some of the melted material then rises up through the overlying Caribbean Plate, fueling the volcanoes of Central America.
See also Eruption on Mount Turrialba, Costa Rica, Eruption on Mount Poás, Costa Rica, Substantial Earthquake in Costa Rica, Eruption on Rincón de la Vieja, Costa Rica and Hydrothermaly heated active seeps from the continental shelf margin, south of Costa Rica.
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