Oceanographic data collected during the EX1504L1 (CAPSTONE NWHI & Johnston Exploration Mapping) expedition on the NOAA Ship OKEANOS EXPLORER in the North Pacific Ocean from July 10, 2015 - July 24, 2015 (NCEI Accession 0131126)

Multibeam and singlebeam mapping operations were conducted 24 hours a day throughout the cruise. Sub-bottom profile mapping was conducted 24 hours a day at the discretion of the CO. Most of the mapping areas pursued during this cruise were never mapped with modern sonar before. Mapping activities focused on three primary areas, (1) some potential underwater cultural heritage sites south of Oahu, (2) the Necker Island area within the Papahanaumokuakea Marine National Monument (PMNM), and (2) the Karin Seamount Chain near Johnston Atoll within the recently expanded Pacific Remote Islands Marine National Monument (PRIMNM).