Higher modes of seismic surface waves: Phase velocities across Scandinavia

Phase velocities of the second modes are determined by correlating the wave trains on seismograms from a network of stations including Uppsala and the USCGS standardized stations in Scandinavia. The phase velocities of the second Rayleigh mode are found to be the same over the whole of Scandinavia with the exception of paths to Kongsberg, which lies among the mountains to the west. The phase velocities, fitted to theoretical curves for an elastic layered earth model which is reasonable for Scandinavia, give a crustal thickness of 40 km.