Focal mechanism in Brazil with waveform modelling

Abstract

Mapping the stress field in intraplate regions is important to help evaluate models of the plate driving forces and geodynamic properties of the upper mantle. In Brazil, the stress field is poorly known and it has been determined mainly using focal mechanisms, some breakout data and a few in-situ measurements. Recently, with the installation of the Brazilian Seismograph Network, the number of events detected has improved, enabling not only a better knowledge of Brazilian seismicity but also allowing more detailed research on topics such as receiver function, tomography and source studies. This internship has as main objective to improve the number of events with focal mechanism determined such as Miranda (2000), Limeira (1997), Bebedouro (2005-2010) using different techniques like first motion P-wave polarity regional/local, waveform modelling and cyclic scanning of the polarity solutions. The results of this work will be useful for future numerical modeling of global/regional intraplate stress field. Furthermore, the increase of Mw determination will help in seismic hazard in Brazil. (AU)