GNGTS 2019 - Atti del 38° Convegno Nazionale

GNGTS 2019 S essione 1.4 225 Results. For a wide range of periods (from 5 s to 30 s), the phase velocities of the study area turned out to be systematically higher than those measured for the Italian peninsula, suggesting a colder geotherm. A methodical evaluation of the uncertainty affecting our data allowed us to discriminate the robust features of the final model. Whereas at crustal depths we observe relatively low standard deviations, larger uncertainties at long periods restrict the reliable seismic images to the study area below Sardinia and southern Corsica. The lateral variations of the VS in the upper crust closely resemble the geology of the study area, highlighting the velocity contrast between the outcropping Variscan basement and the more recent units. Fig. 3 - Vs horizontal slices at different depths. At each depth, the colorscale (in km/s) is set to plus or minus 4% of the mean value. Lithospheric mantle slices, which are only constrained by earthquake-based phase velocities, are blanked where the standard deviations of the phase velocities at 30 s exceed 0.2 km/s.