T. C. Yang
Naval Res. Lab., Washington, DC 20375
During the AREA 88 experiment (Spring of 1988), an ice camp was deployed on an ice floe in the general neighborhood of 78 N and 55 W in the central Arctic. The ice floe became active on and off for a period of days. Many of the noise events were recorded on a planar array of geophones. The response of three-axis geophones were used to analyze the forcing mechanism of the noise events by comparing the geophone response to the ice activities with that generated by man, i.e., hammer blows. Specifically, frequency-wave-number analysis was used to sort out the longitudinal, shear, and flexural waves in the geophone data. While the examples shown here indicate that floe bumping/rubbing was the likely cause for the very-low-frequency noise signals analyzed, long-term accumulative geophone data indicate vertical forcing was the dominant source for ice generated noise.