GSA Annual Meeting in Seattle, Washington, USA - 2017
Paper No. 391-2
Presentation Time: 9:00 AM-6:30 PM
GEOTECTONIC EVOLUTION AND SEISMOTECTONICS OF NORTH FAULTS OF ALGECIRAS FAULT SYSTEM, COLOMBIA
CHICANGANA, German E., Facultad de Ingeniería Civil, Universidad Santo Tomas, Carrera22 Calle 1A Vía Puerto López, Calle 46A N 45 - 14, Villavicencio, 50001, Colombia, BOCANEGRA, Alfonsina, Facultad de Ingeniería Ambiental, Universidad Santo Tomas, Carrera22 Calle 1A Vía Puerto López, Calle 46A N 45 - 14, Villavicencio, 50001, Colombia, KAMMER, Andreas, Departamento de Geociencias, Universidad Nacional de Colombia, Carrera 45 N° 26-85, Edificio Uriel Gutierréz, oficina 506, Bogota D.C, 11001000, Colombia, VARGAS-JIMENEZ, Carlos Alberto, Department of Geosciences, Universidad Nacional de Colombia, Carrera 45 N° 26-85, Edificio Uriel Gutierréz, oficina 215, Ciudad Universitaria, Bogota D.C, 111321, Colombia, SALCEDO HURTADO, Elkin, Observatorio Sismologico del Suroccidente, Universidad del Valle, Edificio 384 - oficina 4012. Ciudad Universitaria Meléndez, Cali, 76001000, Colombia and GOMEZ-CAPERA, Augusto Antonio, Sezione di Milano, Istituto Nazionale di Geofísica e Vulcanologia, via Bassini 15, 20133, Milano, 20121, Italy, germanchicangana@usantotomas.edu.co
The Eastern cordillera of Colombia was originated by the rapid upwelling of Mesozoic and Cenozoic rocks which began 8 millions years ago as a result of the tectonic inversion that occurred in normal faults that originated during the evolution of a Late Triassic basin that appeared when the Pangea supercontinent broke. The thickness of the sediments that constitute in its evolution is basin is 8 km. During Cenozoic the northwestern South America suffered two compresive tectonic (orogenic) phases. The first phase it was due to the final adjust (amalgamation) of Caribbean plate to Northwestern margin of South America during Campanian- Late Eocene lapse and, the second phase that began in Late Oligocene, is due to the adjustment of the subduction under northwest of South America of the Nazca Plate.
The Algeciras Fault System (AFS) is part of the Eastern Frontal Fault System. For the AFS with the help of the historical seismic intensity evaluation and instrumental historical seismicity record (1967 earthquake) have been assigned the 1785, 1827, 1917 and, 1967 historical earthquakes. These earthquakes were felt in Bogota and several Colombian cities located towards the center and southwest of the country. The Guayuriba Fault is reverse with 142,3 km of cumulative length is part of the AFS and corresponds to the northern fault of the fault system. Towards the west of the región where the Guayuriba Fault crosses, there are two semi - parallel reverse faults which are Altamira, and Nazareth.
In this región ocurred recently the earthquakes M = 5.4 and M= 5.0 of october 30, 2016, The earthquake M = 4.7 of december 16, 2016, and the earthquake M = 5.7 of february 6, 2017. The hypocentres of these earthquakes were located by the National Seismological Network of Colombia (RSNC). Also for this región with the historical seismic intensity evaluation have been asigned the historical earthquakes of july 12, 1785 and august 31, 1917.
The location of the epicenters verified here with field work, which are coincident with the location of the hypocenters given by RSNC makes estimate that the asperities are related with the interception in deep between Altamira and Nazareth faults with Guayuriba Fault. In the field work also checked tectonic geomorphology for faults scarps and several geomorphic expressions associated.
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