Crustal structure and surface-wave dispersion. Part II. Solomon Islands earthquake of July 29, 1950

Abstract

Rayleigh waves from the Solomon Islands earthquake of July 29, 1950, recorded at Honolulu, Berkeley, Tucson, and Palisades are analyzed. Both the direct waves and those propagated through the Antipodes were observed for all stations except Honolulu. Application of a correction for land travel results in a dispersion curve for the oceanic portion of the path. It is found that the observed dispersion could be accounted for by propagation through a layer of water 5.57 km. thick overlying simatic rocks having shear velocity 4.56 km/sec. and density 3.0 gm/cc. Basement structure in the Pacific, Indian, South Atlantic, and North Atlantic oceans is identical within the limits of accuracy of the method. The sinusoidal nature and duration of the coda is explained by the effect of the oceans on the propagation of Rayleigh waves. The results are compatible with seismic refraction measurements in the Atlantic and Pacific oceans.