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Oca–Ancón Fault System
Falla Oca-Ancón
Location of the fault in Venezuela
Topographic map of northern Colombia showing the Oca Fault segment
Location	Northern South America
Coordinates	11°00′N 71°45′W / 11.000°N 71.750°W / 11.000; -71.750
Country	Colombia  Venezuela
Region	Caribbean
State	La Guajira Falcón, Zulia
Cities	Maracaibo
Characteristics
Range	Sierra Nevada de Santa Marta, Serranía del Perijá, Venezuelan Coastal Range
Part of	Andean faults
Segments	Oca, Ancón
Length	830 km (520 mi)
Strike	275 ± 7 (W-E)
Dip angle	Vertical to subvertical
Displacement	0.2–2 mm (0.0079–0.0787 in)/yr
Tectonics
Plate	South American
Status	Active
Earthquakes	1834
Type	Strike-slip fault
Movement	Dextral
Age	Late Pleistocene-Holocene
Orogeny	Andean

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). The Oca–Ancón Fault System is part of the diffuse boundary between the Caribbean plate and the South American plate. The movement rate of the Oca–Ancón Fault System is estimated at 2 millimetres (0.079 in) each year, more than most Venezuelan faults.

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.

References

1. ^ Paris et al., 2000, p.9
2. ^ Audemard et al, 2006
3. Audemard et al., 1996a
4. Audemard et al., 1996b

Bibliography

• Audemard M., Franck A.; Singer P., André; Soulas, Jean-Pierre (2006), "Quaternary faults and stress regime of Venezuela" (PDF), Revista de la Asociación Geológica Argentina, 61 (4), Asociación Geológica Argentina: 480–491, retrieved 2015-11-24
• Audemard M., Franck A.; Singer P., André (1996a), "Active fault recognition in northwestern Venezuela and its seismogenic characterization: Neotectonic and paleoseismic approach", Geofísica Internacional, 35 (3): 245–255, doi:10.22201/igeof.00167169p.1996.35.3.460
• Audemard M., Franck A. (1996b), "Paleoseismicity studies on the Oca-Ancón fault system, northwestern Venezuela", Tectonophysics, 259 (1–3): 67–80, doi:10.1016/0040-1951(95)00144-1
• Paris, Gabriel; Machette, Michael N.; Dart, Richard L.; Haller, Kathleen M. (2000), Map and Database of Quaternary Faults and Folds in Colombia and its Offshore Regions (PDF), USGS, pp. 1–66, retrieved 2017-06-20

• Colombia
• Earth sciences
• Geology
• Venezuela

v t e Major South American geological features
Tectonic plates	Antarctic Caribbean Cocos Coiba Malpelo Nazca North Andes Scotia South American
Cratons and shields	Amazonian Craton Arequipa-Antofalla Craton Atlantic Shield Central Brazilian Shield Guiana Shield Paranapanema Block Río Apa Craton Río de la Plata Craton São Francisco Craton Uruguayan Shield
Structures undergoing subduction	Antarctic plate Carnegie Ridge Chile Rise Juan Fernández Ridge Malpelo Ridge Nazca plate Nazca Ridge
Faults and shear zones	Atacama Boconó Bucaramanga-Santa Marta Cochabamba Cordillera Blanca Córdoba Dolores-Guayaquil Domeyko Eastern Frontal Gastre Huincul Liquiñe-Ofqui Magallanes-Fagnano Meta Morón Oca-Ancón Pernambuco El Pilar Romeral San Ramón Sarandí del Yí Sierra Ballena Sobral El Tigre Trans-Brazilian
Rifts and grabens	Aguapeí Amazon Rift Asunción Rift Cuyo Rift Espino Neuquén Rifts Paramirim Salta Rifts
Sedimentary basins	Altiplano Amazon Andean foreland Central Brazil Chaco Colorado Cuyo Eastern Venezuela Golfo San Jorge Magallanes Malvinas Neuquén Pantanal Paraíba Paraná Salta Solimões
Orogenies	Andean Brasiliano Cariri Velhos Chonide Famatinian Gondwanide Juruá Pampean San Rafael Sunsás Terra Australis Tilcarian
Metallogenetic provinces	Bolivian Tin Belt Chilean Iron Belt Deseado Massif El Indio Gold Belt El Mutún Iron Quadrangle Lithium Triangle Pampean Pegmatite Province
Volcanism	Volcanic provinces Andean North Central South Austral Caribbean Central Atlantic Paraná and Etendeka Hotspots Ascension Noronha hotspot Galápagos Juan Fernández San Felix Trindade

v t e Tectonism in Colombia
Tectonic plates	Caribbean plate Coiba plate Malpelo plate North Andes plate Panama plate South American plate
Terranes	Chibcha Tahamí Caribe La Guajira Arquía Quebradagrande Anacona Amazonian Craton Río Negro-Juruena
Terrane-bounding fault systems	Bagre Norte Bucaramanga-Santa Marta (BSF) Cimitarra Cucuana Eastern Frontal (EFS) Afiladores Algeciras Garzón-Pitalito Guaicáramo Guayuriba Mocoa San Pedro-Cumaral Servitá-Santa María Sibundoy Suazá Yopal Boconó Mulato-Getudo Oca Otú Norte Palestina Romeral (RFS) Armenia Buesaco-Aranda Córdoba-Navarco Montenegro Paraíso Piendamó Rosas-Julumito
Intraterrane faults	Chibcha Bituima–La Salina Bogotá Caño Tomás Chitagá-Pamplona La Dina Honda Ibagué Irlanda La Macarena La Plata Suárez Tarra Usme Vianí Tahamí Espiritú Santo Uramita Caribe Abriaquí Argelia Bagre Norte Bahía Solano Cañasgordas Cauca Garrapatas Murindó Murrí Mutatá Montería Naya-Micay Piedrancha Remolino-El Charco Santa Rita El Tambor Toro Tucurá Unguía Urrao La Guajira Cuisa Other terranes Meta Dagua-Calima Guáitara Morronegro-Las Mercedes
Major earthquakes	1646 1743 1785 1827 1834 1868 1875 1906 1917 1936 1958 1962 1967 1970 (1) 1970 (2) 1979 (1) 1979 (2) 1983 1987 1991 1992 1994 1995 (1) 1995 (2) 1996 1999 2004 2007 2008 2012 2013 (2) 2015 2016 (1) 2016 (2)
Orogenies	Andean Famatinian Sunsás Rondônia-Juruá Tapajós Transamazonian Carajas-Imataca
Other topics	Bucaramanga Nest Vichada Structure
Sources	Paris, Gabriel; Machette, Michael N.; Dart, Richard L.; Haller, Kathleen M. (2000). Map and Database of Quaternary Faults and Folds in Colombia and its Offshore Regions (PDF). USGS. pp. 1–66. Retrieved 2017-06-20.       Gómez Tapias, Jorge; Montes Ramírez, Nohora E.; Almanza Meléndez, María F.; Alcárcel Gutiérrez, Fernando A.; Madrid Montoya, César A.; Diederix, Hans (2015). Geological Map of Colombia. Servicio Geológico Colombiano. pp. 1–212. Retrieved 2019-10-29.       Various authors (2014). Enciclopedia de desastres naturales históricos de Colombia (PDF). Universidad del Quindío. pp. 1–21. Retrieved 2017-06-20.
Category • Images

• Seismic faults of Colombia
• Seismic faults of Venezuela
• Strike-slip faults
• Active faults
• Geography of Falcón
• Geography of La Guajira Department
• Geography of Zulia
• Venezuelan Coastal Range
• Colombia–Venezuela border