Oca-Ancón Fault System

11°00′N 71°45′W / 11.000°N 71.750°W / 11.000; -71.750Country Colombia
 VenezuelaRegionCaribbeanStateLa Guajira
Falcón, ZuliaCitiesMaracaiboCharacteristicsRangeSierra Nevada de Santa Marta, Serranía del Perijá, Venezuelan Coastal RangePart ofAndean faultsSegmentsOca, AncónLength830 km (520 mi)Strike275 ± 7 (W-E)Dip angleVertical to subverticalDisplacement0.2–2 mm (0.0079–0.0787 in)/yrTectonicsPlateSouth AmericanStatusActiveEarthquakes1834TypeStrike-slip faultMovementDextralAgeLate Pleistocene-HoloceneOrogenyAndean

The Oca-Ancón Fault System (Spanish: Falla Oca-Ancón) is a complex of geological faults located in northeastern Colombia and northwestern Venezuela near the Caribbean Sea. The fault system is of right-lateral strike-slip type and extends for an approximate length of 830 km (520 mi).^[1][2][3] The Oca-Ancón Fault System is part of the diffuse boundary between the Caribbean Plate and the South American Plate.^[4] The movement rate of the Oca-Ancón Fault System is estimated at 2 millimetres (0.079 in) each year, more than most Venezuelan faults.^[2]

Oca Fault segment

The vertical to subvertical Oca Fault segment in the western part of the fault system has a length of 265 kilometres (165 mi), running west–east through La Guajira, Colombia. It forms the northern boundary of the Sierra Nevada de Santa Marta and cuts through the Serranía del Perijá continuing into Venezuela. The fault segment with a slip rate of 0.2 to 0.8 millimetres (0.0079 to 0.0315 in) per year has been active since the Late Pleistocene (~15,000 years ago) and its most recent activity has been registered in 1834.^[1]

References

Bibliography

• Audemard M., Franck A.; André Singer P., and Jean-Pierre Soulas. 2006. Quaternary faults and stress regime of Venezuela. Revista de la Asociación Geológica Argentina 61(4). 480–491. Accessed 2015-11-24.
• Audemard M., Franck A., and André Singer P.. 1996a. Active fault recognition in northwestern Venezuela and its seismogenic characterization: Neotectonic and paleoseismic approach. Geofísica Internacional 35(3). 245–255. Accessed 2017-06-20.
• Audemard M., Franck A.. 1996b. Paleoseismicity studies on the Oca-Ancón fault system, northwestern Venezuela. Tectonophysics 259(). 67–80. Accessed 2017-06-20.
• Paris, Gabriel; Michael N. Machette; Richard L. Dart, and Kathleen M. Haller. 2000. Map and Database of Quaternary Faults and Folds in Colombia and its Offshore Regions, 1–66. USGS. Accessed 2017-06-20.