The 1950 Calama earthquake occurred near the

Argentina–Chile border The Argentina–Chile border is the longest international border of South America and the third longest in the world after the Canada–United States border and the Kazakhstan–Russia border. With a length of , it separates Argentina from Chile a ...

with an epicenter near Calama, Chile in the

Atacama Desert The Atacama Desert () is a desert plateau located on the Pacific Ocean, Pacific coast of South America, in the north of Chile. Stretching over a strip of land west of the Andes Mountains, it covers an area of , which increases to if the barre ...

on December 9. The event had a hypocenter depth of 113.9 km, beneath the Caichinque volcanic complex. It measured magnitude 8.2 on the

moment magnitude scale The moment magnitude scale (MMS; denoted explicitly with or Mwg, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. was defined in a 1979 paper ...

, making it the largest intermediate depth earthquake ever recorded on Chilean soil. One person was killed and an unspecified number of people were injured in Calama.

Tectonic setting

Earthquakes are frequent in Chile as it lies in the so-called Pacific Ring of Fire, where many of the world's active volcanoes and seismic activities are concentrated at. Off the coast of Chile, the

Nazca Plate The Nazca plate or Nasca plate, named after the Nazca region of southern Peru, is an oceanic list of tectonic plates, tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru– ...

subducts beneath the

South American Plate The South American plate is a major tectonic plate which includes the continent of South America as well as a sizable region of the Atlantic Ocean seabed extending eastward to the African plate, with which it forms the southern part of the Mid ...

along the Peru–Chile or Atacama Megathrust, producing large earthquakes including the 1960 Chilean earthquake which had a magnitude of 9.5–9.6 on the

. In some cases, intraslab earthquakes occur. These earthquakes do not occur on the subduction interface; rather they happen as a result of faulting within the downgoing

. Intraslab earthquakes can occur anywhere within the slab, which may be deeper than 600 km.

Earthquake

The quake was an intermediate-depth event which ruptured within the Nazca Plate. There, the plate dips at an angle of 20°–30° to the east, beneath the

. This was the result of extensional stress acting on the Nazca Plate at an intermediate depth. Based on its large seismic magnitude, the rupture area is estimated to be 6,000 km², breaking through the thickness of the Nazca Plate along a vertically-dipping

normal fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

References

{{Earthquakes in Chile Earthquakes in Chile Earthquakes in Argentina 1950 in Chile 1950 in Argentina 1950 earthquakes History of Antofagasta Region 1950 disasters in Chile 1950 disasters in Argentina 1950 disasters in South America

Tectonic setting

Earthquake

See also

References