Event-driven seismic interferometry with ambient seismic noise

By cross-correlating recordings of ambient seismic noise, one can retrieve the subsurface reflection response. The quality of the retrieved reflections would depend on the qualities of the ambient noise. In a previous study, we cross-correlated ambient-noise data recorded in a desert area in North Africa and showed that we retrieved reflections. This was done assuming that body-wave noise continuously illuminates the recording array. But this is not necessarily true - noise which carries body-wave information can be present only at certain times. We now use only parts of the recorded noise during the correlation process. These parts contain identifiable body-wave events. We show that the results, retrieved only from the noise containing the events, exhibit clearer reflection arrivals.