Purires and Picagres faults and its relationship with the 1990 Puriscal seismic sequence

New morphotectonic, structural, and seismological interpretations have allowed us to define the neotectonics of the region located between the northwestern border of the Talamanca cordillera and the southern flanks of Aguacate Mounts, along the central-western sector of the Central Costa Rican Defor...

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Autores Principales: Montero Pohly, Walter, Rojas Quesada, Wilfredo
Formato: Artículo
Idioma: Español
Publicado: Universidad de Costa Rica 2014
Materias:
Acceso en línea: http://revistas.ucr.ac.cr/index.php/geologica/article/view/15107
https://hdl.handle.net/10669/22460
id 22460
recordtype dspace
spelling 224602021-05-03T22:54:32Z Purires and Picagres faults and its relationship with the 1990 Puriscal seismic sequence Las fallas Purires y Picagres, y su relación con la secuencia sísmica del Puriscal de 1990 Montero Pohly, Walter Rojas Quesada, Wilfredo Neotectonics morphotectonics structural geology seismicity Puriscal shallow seismic sequence of 1990 Neotectónica morfotectónica geología estructural sismicidad secuencia superficial sísmica de Puriscal de 1990 New morphotectonic, structural, and seismological interpretations have allowed us to define the neotectonics of the region located between the northwestern border of the Talamanca cordillera and the southern flanks of Aguacate Mounts, along the central-western sector of the Central Costa Rican Deformed Belt. The principal tectonic structures identified in this study are the Purires, Zapote, Jaris, Bajos de Jorco and Picagres faults. They constitute a set of northwest dextral-slip faults, traversing for more than 45 km the previous mountains ranges. Transtensive and transpressive structures were identified along these faults. Another recognized structure is the Junquillo fault, a predominantly east-west sinistral fault that lies between the Purires and Picagres faults.The three stages of the 1990 Puriscal shallow seismic sequence are reviewed in this study and are related with some of the previous faults. The seismic activity began with a seismic swarm that showed a peak of activity between May and June. The swarm showed a migration of activity between the Picagres and Purires faults. A right-lateral surface fault rupture with a length of 400 m, associated with two seismic events occurred on June 8 (00:31 GMT; Md 4.8) and June 9 (00:34 GMT; Md 4.8), breaks a sector of the eastern branch of Charcón transtensive structure of the Picagres fault. The seismic sequence continued with the Barbacoas earthquake of June 30 (Ms 5.1). This earthquake and its aftershocks located until July 11, rupture a 9 km length segment of the Purires fault. Finally, the Piedras Negras earthquake of December 22, 1990 (Ms 5.7) and its aftershocks occurred until December 30, caused a rupture of 11 km length of the Picagres fault. Nuevas interpretaciones morfotectónicas, estructurales y sismológicas han permitido definir la neotectónica de la región comprendida entre el flanco noroeste de la cordillera de Talamanca y el flanco sur de los Montes del Aguacate, dentro del sector central-oeste del Cinturón Deformado del Centro de Costa Rica. Las principales estructuras tectónicas reconocidas en este estudio son las fallas Purires, Zapote, Jaris, Bajos de Jorco y Picagres. Las mismas constituyenun conjunto de fallas de rumbo noroeste de desplazamiento predominantemente dextral, las cuales atraviesan por más de 45 km, los sistemas montañosos de la zona de estudio. Estructuras transtensivas y transpresivas asociadas con estas fallas son asimismo descritas. Otra estructura identificada es la falla Junquillo, de rumbo cercano al E-W y movimiento sinestral, la cual se ubica entre las fallas Purires y Picagres.Los tres estadios principales de la secuencia sísmica superficial de Puriscal de 1990 son revisados en este estudio y son relacionados con algunas de las anteriores fallas. Esta se inició con un enjambre sísmico que alcanzó su pico de actividad entre mayo y junio. El mismo migró entre las fallas Picagres y Purires. Los eventos sísmicos del 8 de junio(00:31 GMT; Md 4,8) y del 9 de junio (00:34 GMT; Md 4,8), originaron una ruptura de falla lateral derecha de 400m de longitud, a lo largo de un segmento del ramal este de la estructura transtensiva de Charcón, asociada con la falla Picagres.La secuencia sísmica continuó con el terremoto de Barbacoas del 30 de junio (Ms 5,1). Este temblor y la secuencia de réplicas ocurridas hasta el 11 de julio, originó una ruptura de falla de 9 km de longitud, a lo largo de la falla Purires.Finalmente, ocurrió el terremoto de Piedras Negras del 22 de diciembre de 1990 (Ms 5,7). Este sismo y su secuencia de réplicas ocurridas hasta el 30 de diciembre, originaron una ruptura de 11 km de largo a lo largo la falla Picagres. 2014-06-27 2016-05-03T14:24:41Z 2016-05-03T14:24:41Z artículo original http://revistas.ucr.ac.cr/index.php/geologica/article/view/15107 10.15517/rgac.v0i50.15107 https://hdl.handle.net/10669/22460 spa Revista Geológica de América Central; Copyright (c) 2014 Revista Geológica de América Central application/pdf Universidad de Costa Rica Revista Geológica de América Central; Revista Geológica de América Central: Número 50 Revista Geológica de América Central; Revista Geológica de América Central: Número 50 2215-261X 0256-7024
institution Universidad de Costa Rica
collection Repositorio KERWA
language Español
topic Neotectonics
morphotectonics
structural geology
seismicity
Puriscal shallow seismic sequence of 1990
Neotectónica
morfotectónica
geología estructural
sismicidad
secuencia superficial sísmica de Puriscal de 1990
spellingShingle Neotectonics
morphotectonics
structural geology
seismicity
Puriscal shallow seismic sequence of 1990
Neotectónica
morfotectónica
geología estructural
sismicidad
secuencia superficial sísmica de Puriscal de 1990
Montero Pohly, Walter
Rojas Quesada, Wilfredo
Purires and Picagres faults and its relationship with the 1990 Puriscal seismic sequence
description New morphotectonic, structural, and seismological interpretations have allowed us to define the neotectonics of the region located between the northwestern border of the Talamanca cordillera and the southern flanks of Aguacate Mounts, along the central-western sector of the Central Costa Rican Deformed Belt. The principal tectonic structures identified in this study are the Purires, Zapote, Jaris, Bajos de Jorco and Picagres faults. They constitute a set of northwest dextral-slip faults, traversing for more than 45 km the previous mountains ranges. Transtensive and transpressive structures were identified along these faults. Another recognized structure is the Junquillo fault, a predominantly east-west sinistral fault that lies between the Purires and Picagres faults.The three stages of the 1990 Puriscal shallow seismic sequence are reviewed in this study and are related with some of the previous faults. The seismic activity began with a seismic swarm that showed a peak of activity between May and June. The swarm showed a migration of activity between the Picagres and Purires faults. A right-lateral surface fault rupture with a length of 400 m, associated with two seismic events occurred on June 8 (00:31 GMT; Md 4.8) and June 9 (00:34 GMT; Md 4.8), breaks a sector of the eastern branch of Charcón transtensive structure of the Picagres fault. The seismic sequence continued with the Barbacoas earthquake of June 30 (Ms 5.1). This earthquake and its aftershocks located until July 11, rupture a 9 km length segment of the Purires fault. Finally, the Piedras Negras earthquake of December 22, 1990 (Ms 5.7) and its aftershocks occurred until December 30, caused a rupture of 11 km length of the Picagres fault.
format Artículo
author Montero Pohly, Walter
Rojas Quesada, Wilfredo
author_sort Montero Pohly, Walter
title Purires and Picagres faults and its relationship with the 1990 Puriscal seismic sequence
title_short Purires and Picagres faults and its relationship with the 1990 Puriscal seismic sequence
title_full Purires and Picagres faults and its relationship with the 1990 Puriscal seismic sequence
title_fullStr Purires and Picagres faults and its relationship with the 1990 Puriscal seismic sequence
title_full_unstemmed Purires and Picagres faults and its relationship with the 1990 Puriscal seismic sequence
title_sort purires and picagres faults and its relationship with the 1990 puriscal seismic sequence
publisher Universidad de Costa Rica
publishDate 2014
url http://revistas.ucr.ac.cr/index.php/geologica/article/view/15107
https://hdl.handle.net/10669/22460
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