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The lithospheric structure of the western part of Mediterranean Sea is shown by means of S-velocity maps for depths raging from zero to 35 km, determined from the Rayleigh wave analysis. The traces of 55 earthquakes, occurred from 2001 to 2003 in and around the study area, have been used to obtain Rayleigh wave dispersion. These earthquakes were registered by 10 broadband station located on Iberia and the Balearic Islands. The dispersion curves were obtained for periods between 1 and 45 s, by digital filtering with a combination of MFT and TVF filtering techniques. After that, all seismic events were grouped in source zones to obtain a dispersion curve for each source-station path. These dispersion curves were regionalized and after inverted according to generalized inversion theory, to obtain shear-wave velocity models for rectangular blocks with a size of 1°x1°. The shear velocity structure obtained through this procedure is shown in the S-velocity maps plotted for several depths. These results agree well with the geology and other geophysical results previously obtained. The obtained velocity models suggest the existence of lateral and vertical heterogeneity. The shear velocity increases generally with depth for all paths analyzed in the study area.
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