Seismic passive: an experiment for the campus of the National University of Colombia

Abstract:

The generation of seismic image, in areas where the use of active sources it is restricted (like dynamite) or just the area where the area is an active source, it is possible to do it with passive seismic, using seismic interferometry, retrieving the impulse response (Function Green) from the cross-correlation of the ambient noise.

It was cross-correlated ambient seismic noise, of a recording made along a line lying on the university campus in Bogota, on that line were located the virtual-source and the traces. For processing, the surface waves were removed and subsequently, it was applied energy normalization to each of the noise panel and were correlated each noise panels with the trace at the chosen virtual-source position. When it was retrieved common-source gathers it was made a new stacking. And with this stack, seismic image was generated.

The image obtained was compared with the geological surveys of the area and found that the reflectors match, showing 2 matching reflections. It was determined from this study of seismic exploration on one line, using retrieved reflection data it posible to obtain a migrated reflection image
of the subsurface.