Brazilian Lithosphere Seismic Project

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This research is to do a broadband seismic experiment with 10- 15 portable REFTEK/STS-2 seismograph systems to image the continental shield region of SE Brazil. Carnegie Institution, in cooperation with the University of Sao Paulo and other Brazilian institutions, will deploy the seismic array in SE Brazil for a period of 18 months. The structure will be determined by means of seismic wave travel times,wave-form inversion of boundary interaction phases, surface wave inversion and by shear-wave splitting techniques. This shield area was formed and stabilized in late Precambrian time during which a mosaic of heterogeneous cratonic blocks and microplates of varying ages were amalgamated to form the Gondwana supercontinent. The purpose of this study is to increase our understanding of the evolution of the crust and upper mantle of this shield, especially questions related to the thickness of the lithosphere.