Upper crustal velocity structure in Slovenia from Rayleigh wave dispersion

. The inversion of surface-wave dispersion curves can provide information o n the average elastic properties of the upper crustal layers that are usual ly poorly sampled by body waves. The broad band digital records of earthqua kes which recently occurred in Slovenia and neighbouring regions an used to extract the group velocity of the fundamental mode of Rayleigh waves, usin g frequency-time analysis (FTAN). The obtained dispersion curves permit a g ood resolution for the velocity and the thickness of the upper crust. The t hickness of the uppermost sedimentary layer varies between 4 and 6 km and i ts shear-wave velocity is less than 3 km/s. The lower sedimentary layer is 7 to 9 km thick and its shear-wave velocity ranges from about 3.05 km/s in eastern Slovenia, to about 3.25 km/s in western Slovenia. The shear-wave ve locity in the crystalline layer is around 3.5-3.7 km/s in the eastern part, while in the western part it reaches a rather high value of about 3.85 km/ s.