A New Method for the Analysis of Multi-Mode Surface-Wave Dispersion: Application to Love-Wave Propagation in the East Pacific.

摘要

A new technique is presented for simultaneously measuring the average, regional phase velocity of two or more surface-wave modes, even if they travel with the same group velocity. Many observations are required over paths of varying length with earthquake sources of known focal mechanism. The phase of the signal observed at each station can be predicted if the initial phase of the source and the phase velocity and relative amplitude of each mode is known. The square of the difference between the observed phase and the predicted phase is summed over all paths for a set of trial phase velocities. The trial velocities which give the minimum sum correspond to the average phase velocity of each mode. By applying this technique to love-wave data from the east Pacific, the dispersion of the first higher Love mode was measured for the first time in an oceanic area.