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

Anais da Academia Brasileira de Ciências

Ana Catarina A. Moura¹  Paulo H.s. De Oliveira¹  Joaquim M. Ferreira¹  Francisco H.r. Bezerra¹  Reinhardt A. Fuck¹  Aderson F. Do Nascimento¹ 

关键词: Meruoca pluton;    Riacho Fundo fault;    seismological data;    Transbrasiliano Lineament;    granito Meruoca;    falha Riacho Fundo;    estudos de sismicidade;    Lineamento Transbrasiliano;   

DOI  :  10.1590/0001-3765201420130031

来源: SciELO

【 摘 要 】

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.

【 授权许可】

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