PMEL scientists have analyzed the recordings collected from a successful deployment of a deep-ocean hydrophone mooring in Challenger Deep in the Mariana Trench. The Challenger Deep is the deepest known location in Earth's oceans, about 36,000 feet (10,971 meters) beneath the ocean surface. It is located in the Pacific Ocean near Guam. The recordings captured a baleen whale’s call, a magnitude 5.0 earthquake, an overhead typhoon and ship traffic noise. PMEL, in collaboration with the crew of the Coast Guard Cutter Sequoia and with funding from NOAA’s Office of Ocean Exploration and Research, deployed the hydrophone on January 17, 2015 for 22 days. The purpose of the project was to establish a baseline for noise in the deepest part of the Pacific Ocean.