Influence of the continental margin on the stress field and seismicity in the intraplate Acaraú Seismic Zone, NE Brazil

The Borborema province in NE Brazil is characterized by seismic sequences with small earthquakes that can last 10 yr or more. The seismicity in this region is concentrated in three main seismic zones. In this work, we investigate the stress field in one of these zones, the Acaraú Seismic Zone, which...

ver descrição completa

Na minha lista:

Detalhes bibliográficos
Principais autores:	Oliveira, Paulo Henrique Sousa de, Ferreira, Joaquim M., Bezerra, Francisco Hilário Rego, Assumpção, Marcelo, Nascimento, Aderson Farias do, Sousa, Maria O. L., Meneses, Eduardo A. S.
Formato:	article
Idioma:	English
Publicado em:	Oxford University Press (OUP)
Assuntos:	Seismicity and tectonics Continental neotectonics Earthquake source observations
Endereço do item:	https://repositorio.ufrn.br/handle/123456789/31009
Tags:	Adicionar Tag Sem tags, seja o primeiro a adicionar uma tag!

id	ri-123456789-31009
record_format	dspace
spelling	ri-123456789-310092020-12-20T07:59:41Z Influence of the continental margin on the stress field and seismicity in the intraplate Acaraú Seismic Zone, NE Brazil Oliveira, Paulo Henrique Sousa de Ferreira, Joaquim M. Bezerra, Francisco Hilário Rego Assumpção, Marcelo Nascimento, Aderson Farias do Sousa, Maria O. L. Meneses, Eduardo A. S. Seismicity and tectonics Continental neotectonics Earthquake source observations The Borborema province in NE Brazil is characterized by seismic sequences with small earthquakes that can last 10 yr or more. The seismicity in this region is concentrated in three main seismic zones. In this work, we investigate the stress field in one of these zones, the Acaraú Seismic Zone, which is located in the NW part of the Borborema province. This seismic zone exhibits earthquake sequences that contain repeated earthquakes with similar waveforms and a shallow depth. Using a local network, we investigated a seismic sequence close to the town of Santana do Acaraú from December 2009 to December 2010, and we present detailed results (velocity model, hypocentres and focal mechanism) from this network. In addition, we inverted seven focal mechanisms, including six that were used in previous studies, and determined the directions of the three main axes of the regional stress field. Selecting a very precise set of 12 earthquakes, we found an active seismic zone with a depth between 3.5 and 4.8 km and with a horizontal dimension of approximately 2.5 km in the NW–SE direction (azimuth of 118°) and a strike-slip focal mechanism. The new seismic fault and some of the previous seismic faults determined in previous studies occur near the continental-scale Transbrasiliano lineament, but they exhibit no direct relationship with that ancient structure. The stress field is characterized by NW–SE trending compression and NE–SW trending extension. This result suggests that the rheological contrast between the continental–oceanic crusts created flexural stresses with maximum horizontal compression parallel to the continental margin. This stress pattern occurs along the Potiguar basin and continues west as far as the Amazon fan along the Equatorial margin of Brazil. This stress field and related seismicity may be a characteristic of this type of passive margin that is generated during the transform shearing between the South America and Africa plates and that exhibits an abrupt oceanic–continent transition, steep continental slopes and high bathymetric gradients 2020-12-15T21:07:05Z 2020-12-15T21:07:05Z 2015-07-07 article OLIVEIRA, Paulo H.S.; FERREIRA, Joaquim M.; BEZERRA, Francisco H.R.; ASSUMPÇÃO, Marcelo; NASCIMENTO, Aderson F. do; SOUSA, Maria O.L.; MENEZES, Eduardo A.S.. Influence of the continental margin on the stress field and seismicity in the intraplate Acaraú Seismic Zone, NE Brazil. Geophysical Journal International, [S.L.], v. 202, n. 3, p. 1453-1462, 7 jul. 2015. Disponível em: https://academic.oup.com/gji/article/202/3/1453/606045. Acesso em: 22 out. 2020. http://dx.doi.org/10.1093/gji/ggv211. 0956-540X 1365-246X https://repositorio.ufrn.br/handle/123456789/31009 10.1093/gji/ggv211 en Attribution 3.0 Brazil http://creativecommons.org/licenses/by/3.0/br/ application/pdf Oxford University Press (OUP)
institution	Repositório Institucional
collection	RI - UFRN
language	English
topic	Seismicity and tectonics Continental neotectonics Earthquake source observations
spellingShingle	Seismicity and tectonics Continental neotectonics Earthquake source observations Oliveira, Paulo Henrique Sousa de Ferreira, Joaquim M. Bezerra, Francisco Hilário Rego Assumpção, Marcelo Nascimento, Aderson Farias do Sousa, Maria O. L. Meneses, Eduardo A. S. Influence of the continental margin on the stress field and seismicity in the intraplate Acaraú Seismic Zone, NE Brazil
description	The Borborema province in NE Brazil is characterized by seismic sequences with small earthquakes that can last 10 yr or more. The seismicity in this region is concentrated in three main seismic zones. In this work, we investigate the stress field in one of these zones, the Acaraú Seismic Zone, which is located in the NW part of the Borborema province. This seismic zone exhibits earthquake sequences that contain repeated earthquakes with similar waveforms and a shallow depth. Using a local network, we investigated a seismic sequence close to the town of Santana do Acaraú from December 2009 to December 2010, and we present detailed results (velocity model, hypocentres and focal mechanism) from this network. In addition, we inverted seven focal mechanisms, including six that were used in previous studies, and determined the directions of the three main axes of the regional stress field. Selecting a very precise set of 12 earthquakes, we found an active seismic zone with a depth between 3.5 and 4.8 km and with a horizontal dimension of approximately 2.5 km in the NW–SE direction (azimuth of 118°) and a strike-slip focal mechanism. The new seismic fault and some of the previous seismic faults determined in previous studies occur near the continental-scale Transbrasiliano lineament, but they exhibit no direct relationship with that ancient structure. The stress field is characterized by NW–SE trending compression and NE–SW trending extension. This result suggests that the rheological contrast between the continental–oceanic crusts created flexural stresses with maximum horizontal compression parallel to the continental margin. This stress pattern occurs along the Potiguar basin and continues west as far as the Amazon fan along the Equatorial margin of Brazil. This stress field and related seismicity may be a characteristic of this type of passive margin that is generated during the transform shearing between the South America and Africa plates and that exhibits an abrupt oceanic–continent transition, steep continental slopes and high bathymetric gradients
format	article
author	Oliveira, Paulo Henrique Sousa de Ferreira, Joaquim M. Bezerra, Francisco Hilário Rego Assumpção, Marcelo Nascimento, Aderson Farias do Sousa, Maria O. L. Meneses, Eduardo A. S.
author_facet	Oliveira, Paulo Henrique Sousa de Ferreira, Joaquim M. Bezerra, Francisco Hilário Rego Assumpção, Marcelo Nascimento, Aderson Farias do Sousa, Maria O. L. Meneses, Eduardo A. S.
author_sort	Oliveira, Paulo Henrique Sousa de
title	Influence of the continental margin on the stress field and seismicity in the intraplate Acaraú Seismic Zone, NE Brazil
title_short	Influence of the continental margin on the stress field and seismicity in the intraplate Acaraú Seismic Zone, NE Brazil
title_full	Influence of the continental margin on the stress field and seismicity in the intraplate Acaraú Seismic Zone, NE Brazil
title_fullStr	Influence of the continental margin on the stress field and seismicity in the intraplate Acaraú Seismic Zone, NE Brazil
title_full_unstemmed	Influence of the continental margin on the stress field and seismicity in the intraplate Acaraú Seismic Zone, NE Brazil
title_sort	influence of the continental margin on the stress field and seismicity in the intraplate acaraú seismic zone, ne brazil
publisher	Oxford University Press (OUP)
publishDate	2020
url	https://repositorio.ufrn.br/handle/123456789/31009
work_keys_str_mv	AT oliveirapaulohenriquesousade influenceofthecontinentalmarginonthestressfieldandseismicityintheintraplateacarauseismiczonenebrazil AT ferreirajoaquimm influenceofthecontinentalmarginonthestressfieldandseismicityintheintraplateacarauseismiczonenebrazil AT bezerrafranciscohilariorego influenceofthecontinentalmarginonthestressfieldandseismicityintheintraplateacarauseismiczonenebrazil AT assumpcaomarcelo influenceofthecontinentalmarginonthestressfieldandseismicityintheintraplateacarauseismiczonenebrazil AT nascimentoadersonfariasdo influenceofthecontinentalmarginonthestressfieldandseismicityintheintraplateacarauseismiczonenebrazil AT sousamariaol influenceofthecontinentalmarginonthestressfieldandseismicityintheintraplateacarauseismiczonenebrazil AT meneseseduardoas influenceofthecontinentalmarginonthestressfieldandseismicityintheintraplateacarauseismiczonenebrazil
_version_	1773963757235470336

Influence of the continental margin on the stress field and seismicity in the intraplate Acaraú Seismic Zone, NE Brazil

Registros relacionados