[ MHI | NWHI | CNMI-GUAM | AMSAMOA | PRIA]
Main Hawaiian Islands (MHI)
The main Hawaiian Islands are a group of inhabited islands situated in the northern Pacific Ocean. These islands stretch from Ni‘ihau to the big island of Hawai‘i (home to Mauna Loa, the tallest edifice in the world rising 9,500 m from seabed to summit). The main Hawaiian Islands lie at the southeastern end of the Hawaiian archipelago, with the uninhabited Northwest Hawaiian Islands extending toward Asia. Geologically, the main Hawaiian Islands and the Northwest Hawaiian Islands were formed by ‘hotspot’ volcanism that continues today on the island of Hawai‘i. The main Hawaiian Islands are all considered “high” islands, being significantly raised above sea level, and most exhibit both lush mountains and arid plains. The eight islands are: Hawai‘i, Maui, Koho‘olawe, Moloka‘i, Lana‘i, O‘ahu, Kaua‘i and Ni‘ihau.
Northwestern Hawaiian Islands (NWHI)
The Northwestern Hawaiian Islands (NWHI) are a chain of tiny islands, atolls and shoals that spans more than 2000 km of the Pacific. They stretch from Nihoa Island, northwest of the main Hawaiian Islands, to Kure Atoll, northwest of Midway. These islands, atolls and banks are remnants of volcanic islands, originally similar to the volcanoes of the Main Hawaiian Islands, which have eroded and subsided beneath the ocean surface. Geologically, the main Hawaiian Islands and the Northwest Hawaiian Islands make up the Hawaiian Archipelago, which was formed by active volcanism that continues today on the island of Hawai‘i. The main Hawaiian Islands lie at the southeastern end of the Hawaiian archipelago, with the uninhabited Northwest Hawaiian Islands extending toward Asia. The NWHI are uninhabited except for seasonal field camps on a few islands and a small year-round population on Midway. The coral reef ecosystems of the NWHI are unique in that they are some of the healthiest, most undisturbed coral reefs remaining in the world. The NWHI may be the last large-scale predator-dominated coral reef ecosystem on the planet.
Commonwealth of Northern Mariana Islands (CNMI) and Guam
The 290 km long Mariana Archipelago encompasses 14 islands of the U.S. Commonwealth of the Northern Mariana Islands (CNMI) and the U.S. Territory of Guam, as well as numerous offshore banks. The Marianas can be divided into two groups geologically: the older southern island arc that includes Guam, Rota, Tinian, Saipan (&Marpi Bank), Farallon de Mendinilla, and Aguijan and the younger, volcanic northern islands that include Anatahan, Sarigan, Guguan, Alamagan, Pagan, Agrihan, Asuncion, Maug (with Supply Reef) and Farallon de Pajaros.
American Samoa
Very little has been written on the geology and geomorphology of American Samoa. The comprehensive acoustic data sets collected by PIBHMC and its partners allow us to better understand the structures and coral ecosystems around American Samoa. The optical validation data — classified videos and photos of the seafloor — provide additional aid in the interpretation of the multibeam bathymetry and backscatter data, and in the creation of seafloor characterization and benthic habitat maps.
Pacific Remote Island Area (PRIA)
The Pacific Remote Island Area (PRIA) includes seven islands located in the Central Pacific that are under the jurisdiction of the United States. Baker, Howland, and Jarvis Islands, Johnston Atoll, Kingman Reef, and Palmyra Atoll (links are to descriptions on this page) lie between Hawai‘i and American Samoa and are administered as National Wildlife Refuges (NWR) by the U.S. Fish and Wildlife Service (USFWS) of the Dept. of the Interior (DOI). Wake Island, which is located between the Northwestern Hawaiian Islands and Guam, is an unincorporated territory of the U.S. that is administered by the DOI and the U.S. Air Force.