Fluctuation of group velocity of Love waves across a dent in the continental crust

Abstract

The dispersion characteristics of group velocity of Love waves are measured across a dent in the continental crust that has a maximum thickness of about 50 km; the numerical modeling analyses are performed using the finite difference method. Measurement of the group velocity over the entire width of the mountain root displays several distinct dispersions. The group velocities for the crustal dent structure are lower than those for the stratified medium with a maximum crustal thickness of the dent at short periods of 20-30 s. The period range becomes longer as the sloping angle of the dent increases or as the crustal thickness of the dent increases. The period indicating a group velocity minimum for the crustal dent structure is shorter than that for the stratified medium with a maximum crustal thickness of the dent. An example of the interpretation of observational data is shown. In the example, the group velocities for the propagation path over the Tibetan Plateau have properties concordant with the above dispersion characteristics.