The United Sates Geological Survey recorded a Magnitude 4.6 Earthquake at a depth of 32.4 km in eastern Catamarca Province, Argentina, roughly 45 km north of the provincial capitol, also Catamarca, at about 10.45 pm local time on Thursday 10 October 2013 (about 1.45 am on Friday 11 October, GMT). An Earthquake of this magnitude at this depth is unlikely to have caused any damage or injuries, but was probably felt over a wide area.
The approximate location of the 10 October 2013 Catamarca Earthquake. Google Maps.
Catamarca Province is located in the Andes Mountains, one of the most tectonically active mountain ranges in the world, and has a history of earthquakes. The Andes are being formed as the Nazca Plate to the west is subducted beneath the South American Plate. This causes quakes in a number of ways. Firstly there is friction between the two plates as the Nazca Plate passes under South America. Then there is crumpling and upthrust of the South American as it is pushed from the west by the Nazca Plate and from the east by the expansion of the Atlantic. Finally there is volcanic activity in the Andes, as lighter minerals in the Nazca Plate are melted by the heat of the Earth's interior, then rise up through the overlying South American Plate to form volcanoes.
See also Magnitude 4.7 Earthquake in the Sierras de Córdoba, central Argentina, Magnitude 4.4 Earthquake on the Altiplano Plateau in northwest Argentina, Magnitude 4.2 Earthquake in northern Chile, Deep Magnitude 4.5 Earthquake in northwest Argentina and Evacuations ordered after activity on Copahue.
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