The Analysis of the Body and Surface Waves Retrieved from Ambient-noise Recordings

Abstract

We applied seismic interferometry by cross-correlation on two passive seismic dataset recorded in the Mizil area, Romania, to retrieve the body and surface waves. The Mizil area is located next to the seismically active Vrancea zone. The passive measurements were performed in 2009 and 2011 using vertical component geophones planted along two orthogonal directions; geophone spacing was 2.5 m. A number of 1183 noise panels of 16s length were recorded in 2009 and 600 noise panels of 10 s length were recorded in 2011. The spectral analysis of the passive data showed that the noise recorded in 2009 is richer in high frequencies compared to the one recorded in 2011. The body waves were retrieved using ambient-noise recordings without surface waves. By comparing the retrieved waves with those we have seen on active seismic data recorded on a seismic profile in the vicinity of the passive survey, we notice that some of the retrieved waves correspond with geological markers identified on the active seismic data. The surface waves were retrieved using the whole passive data; those reflected waves, at the same time with the surface waves, are not visible, being covered by the surface waves because of their high amplitude.