Acoustic propagation characteristics of the sub-seabed in seismic reflection surveys

Marine seismic reflection surveys provide an abundance of acoustic data that is potentiallyuseful for studying acoustic propagation, in addition to the geoacoustic analysis that can beconducted with these experiments. The data within a single survey and the number of publiclyavailable surveys is well suited for data-driven acoustic analysis. In seismic surveys,propagation of sound through the seabed and sub-seabed is a significant component ofmodeling acoustic transmission loss through the water column. The seabed and sub-seabedprofiles generated from these experiments provide a unique opportunity to simultaneouslyconsider the properties of the seafloor and how these characteristics influence the acousticpropagation over the extent of the array. Here, we will consider data from multiple surveysconducted off the coasts of Oregon, Washington, British Columbia, and Alaska, coveringportions of the Cascadia Subduction Zone and the Queen Charlotte Fault. The research vesselfor these experiments towed a source array composed of 4 streamers, each with 9 airguns,totalling 6600 cubic inches in volume. The receiving array extended up to 15km, containing1200 hydrophone groups with 12.5m spacing and 14-element averaging for each group. Thiswork considers the effects of various seabed and sub-seabed characteristics on acoustictransmission loss in the water column, comparisons with computational models of transmissionloss, and incorporates the necessary adjustments to propagation data based on the source andreceiver array designs [Work supported by ONR].