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 ...

with an epicenter near

Calama, Chile Calama is a city and commune in the Atacama Desert in northern Chile. It is the capital of El Loa Province, part of the Antofagasta Region. Calama is one of the driest cities in the world with average annual precipitation of just . The River L ...

in the

Atacama Desert The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in the ...

on December 9. The event had a

hypocenter In seismology, a hypocenter or hypocentre () is the point of origin of an earthquake or a subsurface nuclear explosion. A synonym is the focus of an earthquake. Earthquakes An earthquake's hypocenter is the position where the strain energy ...

depth of 113.9 km, beneath the

Caichinque Caichinque is a volcanic complex lying between Salar de Talar and ''Salar de Capur'', in the high Andean plateau of the Antofagasta Region, in Chile. It is located southwest of the Salar de Atacama, directly S of Cerro Miñiques and SE of Cord ...

volcanic complex. It measured magitude 8.2 on the

moment magnitude scale The moment magnitude scale (MMS; denoted explicitly with or Mw, 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. It was defined in a 1979 pap ...

, 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 The Ring of Fire (also known as the Pacific Ring of Fire, the Rim of Fire, the Girdle of Fire or the Circum-Pacific belt) is a region around much of the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur. The Ring ...

, 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 tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru–Chile Trench, of the ...

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 Mi ...

along the Peru–Chile or Atacama Megathrust, producing large earthquakes including the

1960 Chilean earthquake The 1960 Valdivia earthquake and tsunami ( es, link=no, Terremoto de Valdivia) or the Great Chilean earthquake (''Gran terremoto de Chile'') on 22 May 1960 was the most powerful earthquake ever recorded. Various studies have placed it at 9.4– ...

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 In any of several fields of study that treat the use of signs — for example, in linguistics, logic, mathematics, semantics, semiotics, and philosophy of language — an extensional context (or transparent context) is a syntactic environment in w ...

stress acting on the Nazca Plate at an intermediate depth. It is the only earthquake with a rupture entirely beneath a continent rather than offshore. 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 tectoni ...

References

{{Earthquakes in Chile Earthquakes in Chile Earthquakes in Argentina 1950 in Chile 1950 in Argentina 1950 earthquakes History of Antofagasta Region

Tectonic setting

Earthquake

See also

References