2015 – USCGC "Sequoia" –– From 10–13 July 2015, the Guam-based 1,930-ton US Coast Guard Cutter "Sequoia" (WLB 215) hosted a team of researchers, under chief scientist Robert P. Dziak, from the NOAA Pacific Marine Environmental Laboratory (PMEL), the University of Washington, and Oregon State University, in deploying PMEL's "Full-Ocean Depth Mooring," a 45-meter-long moored deep-ocean hydrophone and pressure sensor array into the western basin of the Challenger Deep. A 6-hour descent into the western basin anchored the array at ± of water depth, at , about 1 km northeast of "Sumner" deepest depth, recorded in 2010. After 16 weeks, the moored array was recovered 2-4 Nov 2015. "Observed sound sources included earthquake signals (T phases), baleen and odontocete cetacean vocalizations, ship propeller sounds, airguns, active sonar and the passing of a Category 4 typhoon." The science team described their results as "...the first multiday, broadband record of ambient sound at Challenger Deep, as well as only the fifth direct depth measurement."