Seismo-acoustic propagation in an ice-covered Arctic Ocean environment

This paper analyzes a controlled experiment carried out on the polar pack ice to investigate seismo-acoustic propagation in an Arctic Ocean environment. The experiment consisted of deploying three-component geophones on the ice surface, and recording seismo-acoustic waves excited by sledge-hammer blows to the ice and by glass light bulbs imploded at depth in the water column. Seismo-acoustic energy is transmitted to the geophones as seismic plate waves of several types that propagate along the ice layer, and as water-borne acoustic waves that arrive at the underside of the ice below the geophones and couple locally into seismic waves. Understanding the propagation characteristics (polarization, speed, attenuation) and relative importance of these various waves is an important prerequisite to determining the directionality of seismo-acoustic propagation. Wave directionality is exploited to estimate the bearing to acoustic sources in the water column using a rotational analysis enhanced by seismic polarization filtering.