Urrao Fault

The Urrao Fault (Spanish: Falla de Urrao) is a sinistral oblique strike-slip fault in the department of Antioquia in northwestern Colombia. The fault has a total length of 30.5 kilometres (19.0 mi) and runs along an average north to south strike of 003.6 ± 1 in the Western Ranges of the Colombian Andes.

Urrao Fault
Falla de Urrao
Map showing the location of Urrao Fault
Map showing the location of Urrao Fault
EtymologyUrrao
Coordinates06°23′08″N 76°04′58″W
Country Colombia
RegionAndean
StateAntioquia
Characteristics
RangeWestern Ranges, Andes
Part ofAndean oblique faults
Length30.5 km (19.0 mi)
Strike003.6 ± 1
DipVertical
Displacement0.2–1 mm (0.0079–0.0394 in)/yr
Tectonics
PlateNorth Andean
StatusInactive
TypeOblique strike-slip fault
MovementNormal sinistral
AgeQuaternary
OrogenyAndean

Etymology

The fault is named after Urrao.[1]

Description

This set of two parallel faults extend along the axis of the Western Ranges of the Colombian Andes, close to the valleys of the Anacosca and Penderisco Rivers, and the plateau of the Frontino Páramo. Located to the west of the city of Medellín, the faults mainly displace Tertiary sedimentary rocks.[1] The west branch of the fault has mainly normal slip as observed from offset alluvial terraces. The fault forms spectacular fault scarps on terraces. These scarps are 10 kilometres (6.2 mi) long and as much as 50 metres (160 ft) high. Most of the fault trace has a moderate alignment of topographic features, such as linear streams and offset spurs. Quaternary alluvial sediments of the Penderisco River are offset an unknown amount. The slip rate is estimated at 0.2 to 1 millimetre (0.0079 to 0.0394 in) per year deduced from displaced Quaternary sediments.[2]

See also

References

  1. Paris et al., 2000, p.18
  2. Paris et al., 2000, p.19

Bibliography

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

Maps

Further reading

  • Page, W.D. 1986. Seismic geology and seismicity of Northwestern Colombia, 1–200. San Francisco, California, Woodward-Clyde Consultants Report for ISA and Integral Ltda., Medellín.
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