Review of active faults in the Borborema Province, Intraplate South America — Integration of seismological and paleoseismological data

Bezerra, Francisco H.R.; Nascimento, Aderson F. do; Ferreira, Joaquim Mendes; Nogueira, Francisco Cézar Costa; Fuck, Reinhardt A.; Neves, Benjamim B. Brito; Sousa, Maria O.L.

doi:10.1016/j.tecto.2011.08.005

Cited by 100 publications

(44 citation statements)

References 96 publications

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“…The seismicity of the Meruoca granite is similar to that associated with veins and dikes, such as in the Samambaia fault, described by Bezerra et al (2011). The NNW-SSE paleo sigma1 reactivated WNW-ESE structures.…”

Section: Discussionsupporting

confidence: 57%

“…1), established at the end of the Neoproterozoic Brasiliano orogeny (Brito Neves et al 2000). By contrast, seismicity in the Palhano area cuts across the NE-trending Precambrian fabric (Ferreira et al 1998, Bezerra et al 2011). …”

Section: Introductionmentioning

confidence: 99%

“…Seismically-defined faults either reactivate or cut across preexisting structures (Bezerra et al 2011). For example, Ferreira et al (2008) and Lopes et al (2010) concluded that the seismicity in the Caruaru and Belo Jardim areas reactivated the Pernambuco lineament, a continental-scale ductile shear zone ( Fig.…”

Section: Introductionmentioning

confidence: 99%

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Seismogenic faulting in the Meruoca granite, NE Brazil, consistent with a local weak fracture zone

Moura

Oliveira

Ferreira

et al. 2014

An. Acad. Bras. Ciênc.

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A sequence of earthquakes occurred in 2008 in the Meruoca granitic pluton, located in the northwestern part of the Borborema Province, NE Brazil. A seismological study defined the seismic activity occurring along the seismically-defined Riacho Fundo fault, a 081° striking, 8 km deep structure. The objective of this study was to analyze the correlation between this seismic activity and geological structures in the Meruoca granite. We carried out geological mapping in the epicentral area, analyzed the mineralogy of fault rocks, and compared the seismically-defined Riacho Fundo fault with geological data. We concluded that the seismically-defined fault coincides with ~E-W-striking faults observed at outcrop scale and a swarm of Mesozoic basalt dikes. We propose that seismicity reactivated brittle structures in the Meruoca granite. Our study highlights the importance of geological mapping and mineralogical analysis in order to establish the relationships between geological structures and seismicity at a given area.

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Section: Discussionsupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

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Seismogenic faulting in the Meruoca granite, NE Brazil, consistent with a local weak fracture zone

Moura

Oliveira

Ferreira

et al. 2014

An. Acad. Bras. Ciênc.

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“…São Caetano is located in the Boborema province, intraplate setting, which means that earthquakes occur rarely and with small magnitude. The largest event recorded during the past 200 years in this region had a magnitude of m b 5.2 known as Pacajus earthquake, 1980(BEZERRA et al 2011.…”

Section: Studied Area and Data Configurationmentioning

confidence: 99%

Detection of Subtle Hydromechanical Medium Changes Caused By a Small-Magnitude Earthquake Swarm in NE Brazil

D’Hour

Schimmel

Nascimento

et al. 2015

Pure Appl. Geophys.

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Abstract-Ambient noise correlation analyses are largely used in seismology to map heterogeneities and to monitor the temporal evolution of seismic velocity changes associated mostly with stress field variations and/or fluid movements. Here we analyse a small earthquake swarm related to a main m R 3.7 intraplate earthquake in North-East of Brazil to study the corresponding post-seismic effects on the medium. So far, post-seismic effects have been observed mainly for large magnitude events. In our study, we show that we were able to detect localized structural changes even for a small earthquake swarm in an intraplate setting. Different correlation strategies are presented and their performances are also shown. We compare the classical auto-correlation with and without pre-processing, including 1-bit normalization and spectral whitening, and the phase auto-correlation. The worst results were obtained for the pre-processed data due to the loss of waveform details. The best results were achieved with the phase cross-correlation which is amplitude unbiased and sensitive to small amplitude changes as long as there exist waveform coherence superior to other unrelated signals and noise. The analysis of 6 months of data using phase auto-correlation and cross-correlation resulted in the observation of a progressive medium change after the major recorded event. The progressive medium change is likely related to the swarm activity through opening new path ways for pore fluid diffusion. We further observed for the auto-correlations a lag time frequency-dependent change which likely indicates that the medium change is localized in depth. As expected, the main change is observed along the fault.

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“…Faulting also affected the postrift units from the Late Cretaceous to the Quaternary (Bezerra and Vita-Finzi, 2000;Kirkpatrick et al, 2013). These faults reactivate the Precambrian shear zones or basin-bounding faults as well as cut across preexisting structures (Bezerra et al, 2011). …”

Section: Tectonic Settingmentioning

confidence: 99%

Fault evolution in the Potiguar rift termination, equatorial margin of Brazil

Castro

Bezerra

2015

Solid Earth

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Abstract. The transform shearing between South American and African plates in the Cretaceous generated a series of sedimentary basins on both plate margins. In this study, we use gravity, aeromagnetic, and resistivity surveys to identify architecture of fault systems and to analyze the evolution of the eastern equatorial margin of Brazil. Our study area is the southern onshore termination of the Potiguar rift, which is an aborted NE-trending rift arm developed during the breakup of Pangea. The basin is located along the NNE margin of South America that faces the main transform zone that separates the North and the South Atlantic. The Potiguar rift is a Neocomian structure located at the intersection of the equatorial and western South Atlantic and is composed of a series of NE-trending horsts and grabens. This study reveals new grabens in the Potiguar rift and indicates that stretching in the southern rift termination created a WNW-trending, 10 km wide, and ∼ 40 km long right-lateral strike-slip fault zone. This zone encompasses at least eight depocenters, which are bounded by a left-stepping, en echelon system of NW-SE-to NS-striking normal faults. These depocenters form grabens up to 1200 m deep with a rhomb-shaped geometry, which are filled with rift sedimentary units and capped by postrift sedimentary sequences. The evolution of the rift termination is consistent with the right-lateral shearing of the equatorial margin in the Cretaceous and occurs not only at the rift termination but also as isolated structures away from the main rift. This study indicates that the strike-slip shearing between two plates propagated to the interior of one of these plates, where faults with similar orientation, kinematics, geometry, and timing of the major transform are observed. These faults also influence rift geometry.

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Review of active faults in the Borborema Province, Intraplate South America — Integration of seismological and paleoseismological data

Cited by 100 publications

References 96 publications

Seismogenic faulting in the Meruoca granite, NE Brazil, consistent with a local weak fracture zone

Seismogenic faulting in the Meruoca granite, NE Brazil, consistent with a local weak fracture zone

Detection of Subtle Hydromechanical Medium Changes Caused By a Small-Magnitude Earthquake Swarm in NE Brazil

Fault evolution in the Potiguar rift termination, equatorial margin of Brazil

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