title: Seismogenic faulting in the Meruoca granite, NE Brazil, consistent with a local weak fracture zone.
abstract: 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.
authors.affiliation: Universidade de Brasília, Campus Universitário Darcy Ribeiro, Instituto de Geociências, Brasília, DF, Brasil.
authors.forename: Ana Catarina A
authors.initials: AC
authors.lastname: Moura
authors.affiliation: Departamento de Geologia, Universidade Federal do Rio Grande do Norte, Campus Universitário, Natal, RN, Brasil.
authors.forename: Paulo H S
authors.initials: PH
authors.lastname: De Oliveira
authors.affiliation: Departamento de Geologia, Universidade Federal do Rio Grande do Norte, Campus Universitário, Natal, RN, Brasil.
authors.forename: Joaquim M
authors.initials: JM
authors.lastname: Ferreira
authors.affiliation: Departamento de Geologia, Universidade Federal do Rio Grande do Norte, Campus Universitário, Natal, RN, Brasil.
authors.forename: Francisco H R
authors.initials: FH
authors.lastname: Bezerra
authors.affiliation: Universidade de Brasília, Campus Universitário Darcy Ribeiro, Instituto de Geociências, Brasília, DF, Brasil.
authors.forename: Reinhardt A
authors.initials: RA
authors.lastname: Fuck
authors.affiliation: Departamento de Geologia, Universidade Federal do Rio Grande do Norte, Campus Universitário, Natal, RN, Brasil.
authors.forename: Aderson F
authors.initials: AF
authors.lastname: Do Nascimento