Caracterização da atividade sísmica de 2016 no Lineamento Pernambuco, São Caetano, NE Brasil

Abstract

Intraplate seismicity, such as that occurring in the NE of Brazil, presents a lower magnitude and occurs less frequently when compared to the activity in the plate boundaries. Nevertheless, this type of seismic activity can not be disregarded since these events are generally shallow and may occur close to urban areas and may cause significant damage to civil constructions. Therefore, understanding the mechanisms that generate such earthquakes and developing models to explain their occurrence is fundamental for the assessment of seismic hazard and risk around the world. The NE of Brazil is the seismically most active region of the country and has already presented several destructive earthquakes. The seismic activity of this region is characterized by swarms of earthquakes that can last a few months or even several years. These earthquakes occur at shallow depths of up to 12 km and can reach magnitudes higher than 5. In the Northeast of Brazil, a region that presents recurrent seismicity is the municipality of São Caetano - PE. The activity registered in the area is expressive and has been monitored in the last decade by the Seismological Laboratory of UFRN. In 2016 a new seismic sequence was recorded in the locality. Therefore, the objective of this work is to analyze and characterize this recent activity, obtaining hypocentral parameters and focal mechanism. A total of 3 different focal mechanisms were obtained to represent the activity. The variation of the strain is observed as the depth of events increases.