Ocean-bottom geoacoustic measurements in the ice-covered Lincoln Sea

Abstract

Describes a high-resolution seismic experiment designed to measure ocean-bottom geoacoustic properties in the Lincoln Sea, north of Ellesmere Island, Canada. An ocean-bottom seismometer (OBS) was deployed through multi-year sea ice and used to record broadband explosive sources detonated on the bottom at a number of ranges from 65 m to 1200 m. A layered compressional-speed model of the bottom was determined from an analysis of head-wave arrival times. The data set did not lend itself as readily to the estimation of shear properties; however, the shear speed of the surficial sediments was inferred from a Scholte wave arrival, and a shear-speed model is presented which is consistent with this surface value and the compressional-speed model. The importance of including an estimate of shear speed in the geoacoustic model is demonstrated using a numerical propagation model.<>