ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

3aUW1. Determination of sea ice processes using geophone arrays.

Peter J. Stein

Steven E. Euerle

Scientific Solutions, Inc., 18 Clinton Dr., Hollis, NH 03049-6576

Similar to land-based geophysics, seismoacoustic techniques are necessary to study sea ice mechanics. Most ice fracturing can only be detected via the elastic/acoustic waves which radiate. One of the best means of determining the spatially averaged mechanical properties is through probing the ice with elastic waves. Here the results are described from two separate experiments in which large (order 1-km aperture) arrays of triaxial geophones were deployed to study the sea ice mechanical properties via the elastic waves which propagate in the ice. The first test was conducted on ``clean'' first-year shore-fast ice off the coast of Resolute Bay Canada in Spring 1992. The second was a winter-over system deployed on multiyear ice during the Fall 1993 SIMI field operation in the Beaufort Sea (subsequently recovered in March 1994). Additionally, during SIMI an automated ``hammer blow'' source was deployed which impacted the ice every 7 h. Various signal processing and data analysis techniques for studying sea ice processes such as ice growth and thermal fracturing will be described. Results will be presented along with comparisons between first-year and multiyear ice. [Work supported by ONR.]