Abstract

The group velocity vs. frequency curves for 103 different Pacific paths have been analyzed to determine the group velocity dispersion as a function of latitude and longitude in the neighborhood of the group velocity maximum. The main features of the local group velocity dispersion curves can be specified by the maximum group velocity u0, the period t0 at which the maximum occurs, and a factor b related to the curvature of the dispersion curve at its maximum. The highest group velocities are found in the northwest Pacific where u0 exceeds 4.2 km/s. The Andesite line appears as a region of rapid change in u0, t0, and b. The East Pacific Rise is not delimited by the dispersion map, but it occurs in a region of low u0, t0, and b. The principal value of the maps appears to be that they present qualitative information on the crust and upper mantle structure.

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