NOAA and Partners Map the Seafloor in Southernmost Hawaiian Exclusive Economic Zone

In 2023 and 2024, two expeditions supported by NOAA Ocean Exploration resulted in the mapping of more than 31,600 square miles (82,000 square kilometers) of seafloor within the U.S. Exclusive Economic Zone around Hawaiʻi, including more than 3,000 square miles (7,800 square kilometers) in an area informally known as the “Hawaiian crescent” due to its shape. This work is part of a multi-year effort between NOAA, the Ocean Exploration Cooperative Institute (OECI), the U.S. Geological Survey (USGS), and the Bureau of Ocean Energy Management (BOEM) to explore the crescent-shaped region.

This map displays high-resolution seafloor mapping data available around the Main Hawaiian Islands. Data collected during the Jarvis Island Mapping expedition (NA158) on Ocean Exploration Trust’s Exploration Vessel Nautilus and Beyond the Blue: Hawaii Mapping expedition (EX2402) on NOAA Ship Okeanos Explorer are shown in full color, while previously collected data are displayed in grey. The inset shows data collected with the crescent-shaped area of interest for additional exploration. Image courtesy of NOAA Ocean Exploration. Download largest version (4.4 MB).

This region is characterized by largely flat and very deep seafloor, known as the abyssal plain. Located at depths between 9,800 and 19,700 feet (3,000 and 6,000 meters), abyssal plains are one of the largest and least known habitats on Earth. On abyssal plains, environmental conditions can allow for the formation of mineral concretions known as abyssal plain nodules that provide habitat for benthic fauna and can be of interest for seabed mineral resource potential. In the abyssal regions south of Hawaiʻi, oceanographic and geologic evidence indicate that abyssal plain nodules may be present on the seafloor, although no samples have been previously collected.

While nearshore waters surrounding the Main Hawaiian Islands have been relatively well surveyed, offshore areas located further away remain largely unmapped. The seafloor mapping data collected on the abyssal plain far offshore Hawaiʻi during the Jarvis Island Mapping expedition (NA158) on Ocean Exploration Trust’s Exploration Vessel Nautilus in partnership with BOEM, USGS, and OECI and the Beyond the Blue: Hawaiʻi Mapping expedition (EX2402) on NOAA Ship Okeanos Explorer are critical to increasing our understanding of this region. These mapping data, which cover an area more than three times the size of the land area of all of the Hawaiian Islands combined, will help to build the foundation needed to understand the geological and biological context of the area, allowing scientists to better characterize the abyssal plain ecosystem and potential abyssal plain nodule occurrence south of Hawaiʻi.

In Fall 2025, scientists from the U.S. Geological Survey, the University of Hawaiʻi at Mānoa, Scripps Institution of Oceanography, the Japan Agency for Marine-Earth Science and Technology, and the Bureau of Ocean Energy Management will build upon the data collected during the previous expeditions as they conduct an expedition to study characterize abyssal plain geology, including any nodules present, as well as seafloor and water column fauna and ecosystem structure, and carbon dynamics in the “Hawaiian crescent.”

• Access data from the Jarvis Island Mapping expedition (NA158)
• Access data from the Beyond the Blue: Hawaiʻi Mapping expedition (EX2402)

This map displays high-resolution seafloor mapping data available around the Main Hawaiian Islands. Data collected during the Jarvis Island Mapping expedition (NA158) on Ocean Exploration Trust’s Exploration Vessel Nautilus and Beyond the Blue: Hawaii Mapping expedition (EX2402) on NOAA Ship Okeanos Explorer are shown in full color, while previously collected data are displayed in grey. The crescent-shaped region outlined in white is of particular interest for future exploration. Image courtesy of NOAA Ocean Exploration. Download largest version 3.9 MB).