Study of the deep structure of the Borborema Province in relationship with the environmental seismic noise
Ambient Seismic Noise; Cross-Correlation; Seismic Interferometry; Body Waves; Borborema Province.
The analysis of earthquakes that occur every day on earth was one of the main methods that led to the development of models for the deep structure of the planet. These models were based on recordings of body and surface waves radiated by earthquakes that occur in geologically active areas, especially at the boundary between plates. However, the location of earthquakes along the edges of the plates, results in a major deficiency: A limited resolution in all other areas where earthquakes are not present, as in Brazil, which is located with in the South American plate. By contrast, even in areas with very low levels of seismicity, we have the constant movement of the earth's surface that is not related to tectonic activity, which is known as the seismic ambient noise. Previous works have shown that cross-correlations of seismic noise recorded simultaneously at two points and their subsequent stacking - collectively known as seismic interferometry - allow the reconstruction of surface waves propagating between these points and that, under certain conditions, body waves can also be reconstructed. The present work is to use new methods of seismic interferometry to determine whether or not it is possible to extract signal from, the ambient seismic noise to also recover the body waves (P and S) signature in NE Brazil. If so, this will have important implications for the imaging and geophysical characterization of intraplate areas in general.