Upper crustal earthquake swarms in São Caetano: Reactivation of the Pernambuco shear zone and trending branches in intraplate Brazil

Neto, H. C. Lima; Ferreira, Joaquim Mendes; Bezerra, Francisco H.R.; Assumpção, Marcelo; Nascimento, Aderson F. do; Sousa, Maria O.L.; Menezes, E. A.

doi:10.1016/j.tecto.2013.08.001

Cited by 29 publications

(11 citation statements)

References 32 publications

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“…The authors interpreted those large Vp/Vs ratios as resulting from extensive intrusion of the upper crust by mafic material during the formation of the passive margin. We find upper crustal Vp/Vs ratios of 1.83-1.85 at the coastal stations inconsistent with corresponding bulk Vp/Vs ratios of 1.67-1.75 for the entire crust (Pavão et al, 2013), as they would imply lower crustal lithologies with implausible Vp/Vs ratios, and also inconsistent with Vp/Vs ratios around 1.71 inferred from shallow, local seismicity (Ferreira et al, 1998;Lima Neto et al, 2013). We think that the preferential development of an intra-crustal discontinuity within regions of thin crust suggests this is a feature related to crustal thinning.…”

Section: An Intra-crustal Detachment Zonecontrasting

confidence: 91%

“…The receiver function waveforms are the same as those developed in Luz et al (2015), which were utilized to investigate lateral variations in crustal thickness and bulk Vp/Vs ratio across the Borborema Province. Nonetheless, we expanded the dataset by developing new receiver function estimates at a number of short-period stations belonging to aftershock deployments in the Province (Ferreira et al, 1998;Lima Neto et al, 2013). We followed the same approach as in Luz et al (2015), and selected seismic sources between 30°and 90°epicentral distance with magnitude 5.5 m b or larger.…”

Section: Common Conversion Point Migration and Stackingmentioning

confidence: 99%

“…The INCT-ET temporary deployments included a seismic line of 8 broadband stations crossing the Borborema Province and a network of 16 short-period stations, widespread throughout the Province, which operated continuously for 1 to 1.5 years. It also included a number of short-period, aftershock networks that operated for short periods of time (e.g., Ferreira et al, 1998;Lima Neto et al, 2013). The RSISNE network, on the other hand, consists of 16 broadband stations that have been monitoring seismic activity in NE Brazil continuously since December 2010.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Crustal architecture of the Borborema Province, NE Brazil, from receiver function CCP stacks: Implications for Mesozoic stretching and Cenozoic uplift

2015

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Section: An Intra-crustal Detachment Zonecontrasting

confidence: 91%

Section: Common Conversion Point Migration and Stackingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Crustal architecture of the Borborema Province, NE Brazil, from receiver function CCP stacks: Implications for Mesozoic stretching and Cenozoic uplift

2015

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“…Esse tipo de modelo é aceitável, pois a rede apresenta estações bem próximas à área epicentral, instaladas sobre o embasamento Pré-Cambriano, constituído de rochas consolidadas e de baixa atenuação. O modelo de semiespaço tem sido utilizado desde 1986 (por exemplo Ferreira et al, 1987;Ferreira et al, 1998;Lima Neto et al, 2013;Oliveira et al, 2015).…”

Section: Aquisição Análise De Dados E Modelo De Velocidadesunclassified

“…Outro resultado importante obtido tem relação com a reativação de grandes zonas de cisalhamento. Ficou demonstrado que o Lineamento Pernambuco está reativado em alguns trechos (Ferreira et al, 1998(Ferreira et al, , 2008Lima Neto et al, 2013). No entanto, não há evidências de que o Lineamento Sobral-Pedro II esteja reativado (Oliveira et al, 2015).…”

Section: Discussões E Conclusãounclassified

Sismicidade intraplaca em Pedra Preta (RN) no período de 2013 a 2014

Costa

Ferreira

Neto

et al. 2017

Geol. USP. Sér. Cient.

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ResumoA atividade sísmica em Pedra Preta (RN), localizada no Nordeste do Brasil, região de maior sismicidade intraplaca do país, teve início em dezembro de 2010. Antes disso, não havia registro de sismos na área. Durante o ano de 2013 e início de 2014, a rede sismográfica de Pedra Preta registou 273 sismos locais em 3 ou mais estações. Desses eventos foram selecionados os 50 com melhor leitura dos tempos de chegada das ondas P e S, sendo determinado o modelo de velocidades (V p /V s = 1,72 e V p = 5,90 km/s) e calculados os hipocentros, com o programa HYPO71. Para a determinação do mecanismo focal composto foi realizada uma nova seleção de sismos obedecendo critérios mais restritos para os hipocentros (epicentros localizados dentro da rede com resíduo médio de tempo de chegada ≤ 0,01 s, número de observações ≥ 10, erro médio na horizontal < 0,1 km, erro médio na vertical < 0,1 km), tendo sido selecionados por esses critérios 24 eventos. Os hipocentros desses sismos mostram que a falha sismogênica tem aproximadamente 3 km de extensão, com sismos de 2,3 a 5,8 km de profundidade. Os parâmetros da falha sismogênica foram obtidos pela combinação do método dos mínimos quadrados e do programa FPFIT (strike = 254º, dip = 67º e rake = -66º), caracterizando uma falha normal. Os epicentros e o mecanismo focal foram utilizados para verificar se havia ou não possível correlação com feições geológicas mapeadas na área. A conclusão é que não existem feições geológicas mapeadas que possam estar relacionadas diretamente com a atividade sísmica estudada.Palavras-chave: Atividade sísmica; Determinação hipocentral; Mecanismo focal; Falhas sismogênicas; Sismotectônica. AbstractThe seismic activity in Pedra Preta (RN), Northeast of Brazil, region of main intraplate seismicity of the country, began in December 2010. Before that year, there was no record of earthquakes in this area. During 2013 and early 2014, the seismographic network deployed in Pedra Preta registered 273 local earthquakes in 3 or more stations. Of these, 50 events with the best readings of the arrival times of the P and S waves were selected to determine velocity model (V p /V s = 1.72 and V p = 5.90 km/s) and their hypocenters were calculated, with HYPO71 software. For the determination of the composed focal mechanism, it was realized a new selection with earthquakes obeying more stringent criteria for the hypocenters (epicenters located within the network with mean arrival-time residue ≤ 0.01 s, number of observations ≥ 10, mean horizontal error < 0.1 km, mean vertical error < 0.1 km), having been selected 24 events by these criteria. The hypocenters of earthquakes show that the seismogenic fault is about 3 km long, with earthquakes between 2.3 and 5.8 km deep. The parameters of seismogenic fault were obtained by combining the method of least squares and FPFIT software (strike = 254º, dip = 67º and the rake = -66º), indicating a normal fault. The hypocenters and focal mechanism were used to verify if there was possible correlation with geological features mapped i...

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The Paradigm of Stable Intraplate Regions and Neotectonics in Northeastern Brazil

Maia

Bezerra

2019

Structural Geomorphology in Northeastern Brazil

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Upper crustal earthquake swarms in São Caetano: Reactivation of the Pernambuco shear zone and trending branches in intraplate Brazil

Cited by 29 publications

References 32 publications

Crustal architecture of the Borborema Province, NE Brazil, from receiver function CCP stacks: Implications for Mesozoic stretching and Cenozoic uplift

Crustal architecture of the Borborema Province, NE Brazil, from receiver function CCP stacks: Implications for Mesozoic stretching and Cenozoic uplift

Sismicidade intraplaca em Pedra Preta (RN) no período de 2013 a 2014

The Paradigm of Stable Intraplate Regions and Neotectonics in Northeastern Brazil

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