A map showing variation of Rayleigh wave group
A map showing variation of Rayleigh wave group A map showing variation of Rayleigh wave (a type of seismic surface wave) group velocity for 8 sec period vibrations derived from more than 60,000 measurements. By cross correlating up to three years of continuous data from 512 western U.S. stations, including the EarthScope USArray Transportable Array and regional seismic networks, inter-station propagation velocities for all available station pairs were recovered and inverted for regional velocity structure. Thick black lines define major tectonic province boundaries. (Image courtesy of M.P. Moschetti, M.H. Ritzwoller, and N.M. Shapiro.)