Rapid, Basin-Wide Surveying of Large Undersea Topography Using Scattered Acoustic Energy

An acoustic experimental and processing technique is under development to provide rapid, wide-area reconnaissance of large undersea topography. The technique uses explosive sources and a commercial seismic array receiver to obtain topographic reverberation data covering radial distances of over 500 n.mi. After filtering and beamforming, the processing provides spatial stabilization of beams and averaging over multiple shots to correct for left-right ambiguities and to create basin-wide mappings of the major scatterers. The concept is illustrated using data from two basin areas, one northeast of New Zealand, and the other in the Canary Basin. The resultant latitude/longitude display of the location and strength of major scatterers reveals both known and uncharted features. The technique is intended to both complement other remote sensing techniques such as magnetics and altimetry, as well as provide initial reconnaissance results to guide more detailed survey operations. We discuss preliminary analysis to quantify the size of major topographic features from the level of their scattered return.