I. Introduction
There was an urgent concern in the 1970s with use of low-frequency ocean acoustics (less than 500 Hz) for long-range detection of nuclear submarines. Comprehensive measurement exercises were done in broad ocean areas. Some of the data potentially are valuable for expanded analysis with modern computational tools. This paper describes recovery, analysis, and interpretation of acoustic data collected at a submerged buoy site in the northeast Pacific Ocean. The experiment was designed to isolate ambient noise generated by local wind and surface shipping by means of hydrophones positioned beneath the deep sound channel (below critical depth). Data also were taken in the sound channel.