The La Plata or Chusma Fault (Spanish: Falla de La Plata, Falla de Chusma) is a dextral oblique thrust fault in the department of Huila in southwestern Colombia. The fault has a total length of 113.2 kilometres (70.3 mi) and runs along an average northeast to southwest strike of 039 ± 12 in the Central Ranges of the Colombian Andes.

La Plata Fault
Chusma Fault, Falla de La Plata, Falla de Chusma
Map showing the location of La Plata Fault
Map showing the location of La Plata Fault
EtymologyLa Plata
Coordinates02°15′42.6″N 76°00′03.2″W / 2.261833°N 76.000889°W / 2.261833; -76.000889
Country Colombia
RegionAndean
StateHuila
CitiesLa Plata, Teruel
Characteristics
RangeCentral Ranges, Andes
Part ofAndean oblique faults
Length113.2 km (70.3 mi)
Strike039 ± 12
DipWest
Dip angle40-60
Displacement0.2–1 mm (0.0079–0.0394 in)/yr
Tectonics
PlateNorth Andean
StatusActive
Earthquakes1967, 1996
TypeOblique thrust fault
MovementDextral reverse
Rock unitsHonda Group
AgeQuaternary
OrogenyAndean

Etymology

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The fault is named after La Plata, Huila.[1]

Description

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The La Plata or Chusma Fault extends across the eastern slope of the Central Ranges of the Colombian Andes, southeast of the city of Neiva in southwestern Colombia. The fault displaces Triassic, Jurassic and Cretaceous sedimentary rocks, as well as Tertiary volcanic rocks. Coalescent Quaternary alluvial fan deposits are offset by the La Plata Fault. The trace is characterised by old retreated and declined scarps, en-echelon semiparallel associated faults that cut alluvial deposits of the Páez River and local lahar deposits, a well developed topographic fault-line expression, and a probable pull-apart basin filled with Quaternary alluvial fans and alluvium near the town of La Plata. The slip rate has been estimated at 0.2 to 1 millimetre (0.0079 to 0.0394 in) per year based on geomorphologic expression.[1] Activity of the fault in 1967 and 1996 has been registered.[2]

See also

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References

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  1. ^ a b Paris et al., 2000a, p.57
  2. ^ (in Spanish) La Chusma puso en alerta a Teruel - El Tiempo

Bibliography

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  • Paris, Gabriel; Machette, Michael N.; Dart, Richard L.; Haller, Kathleen M. (2000a), Map and Database of Quaternary Faults and Folds in Colombia and its Offshore Regions (PDF), USGS, pp. 1–66, retrieved 2017-09-18

Maps

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