R. D. Huston
S. E. Dosso
Defence Res. Establishment Pacific, FMO Victoria, BC V0S 1B0, Canada
In situ shear speed measurements for ocean bottom sediments are especially difficult to obtain in the Arctic. A novel experiment was performed in a shallow water Arctic environment in April 1991 to determine shear speeds from measurements of the reflection coefficient at the ocean floor as a function of grazing angle. The receiver was composed of a vertical array of nine hydrophones spanning 210 m and suspended from the ice in 320 m of water. Imploding light bulbs were used as acoustic sources at various depths and ranges. Compressional speeds required for shear speed estimation were determined by a conventional refraction method using 1.1-oz explosive charges detonated on the ocean floor at various ranges and with an ocean bottom seismometer as the receiver. Estimates of shear speed were obtained by fitting the data to classical expressions for reflection coefficients from an elastic half-space.