Detection of the Kauai Beacon signal on Ocean Networks Canada’s hydrophones in the NE Pacific

We present a study of the Kauai Beacon signal as received by the hydrophones of Ocean Networks Canada’s (a University of Victoria Initiative) NorthEast Pacific Time-series Undersea Networked Experiments (NEPTUNE) observatory. Long range acoustic-propagation studies are used to produce basin-scale estimates of the variability of bulk ocean temperature and transmission loss. The Kauai Beacon source, located off of the north shore of the Hawaiian Island of Kauai, was designed to support such studies and has resumed its transmissions on a regular schedule since 2023. At a distance of approximately 4100 km from the Kauai Beacon and a depth close to the deep sound channel axis, the NEPTUNE stations around the Barkley Canyon have an unobstructed path to the source. Though Ocean Networks Canada has had a four-element volumetric array of Ocean Sonics icListen HF hydrophones at the “Barkley Node” site since 2021, a single low-frequency icListen AF hydrophone was deployed in the summer of 2024 at the “Barkley Upper Slope” site, specifically for the purpose of supporting the reception of the Kauai Beacon signal.