Estudos preliminares da anisotropia sísmica em Senador Sá-CE

In the João Câmara and Açu areas, NE Brazil, the Precambrian fabric has been interpreted as predominantly controlling the crustal seismic anisotropy. This interpretation is due the polarization of the fastest S wave splitting which is parallel to Precambrian lineaments. The seismic activity in Senador Sá occurred between two shear zones. Initially, two stations presented the NE and NNE polarization; and delay time 8.16 ms/km and 2.56 ms/km. The investigation of regional lineaments shows that these features present a NE trend, which is compatible with our preliminary seismic anisotropy study. A detailed study using other stations located between the shear zones could shed further light on this issue and confirm or not the Precambrian-controlled seismic anisotropy in NE Brazil.