Подводный вулкан Камаэхуаканалоа у берегов Гавайев

Active submarine volcano off the southeast coast of the island of Hawaii

Kamaʻehuakanaloa Seamount (previously known as Lōʻihi) is an active submarine volcano about off the southeast coast of the island of Hawaii. Kamaʻehuakanaloa is the newest volcano in the Hawaiian–Emperor seamount chain, a string of volcanoes that stretches about northwest of Kamaʻehuakanaloa. Unlike most active volcanoes in the Pacific Ocean that make up the active plate margins on the Pacific Ring of Fire, Kamaʻehuakanaloa and the other volcanoes of the Hawaiian–Emperor seamount chain are hotspot volcanoes and formed well away from the nearest plate boundary. Volcanoes in the Hawaiian Islands arise from the Hawaii hotspot, and as the youngest volcano in the chain, Kamaʻehuakanaloa is the only Hawaiian volcano in the deep submarine preshield stage of development. Kamaʻehuakanaloa began forming around 400,000 years ago and is expected to begin emerging above sea level about 10,000–100,000 years from now. At its summit, Kamaʻehuakanaloa Seamount stands more than above the seafloor, making it taller than Mount St. Helens was before its catastrophic 1980 eruption. A diverse microbial community resides around Kamaʻehuakanaloa many hydrothermal vents. In the summer of 1996, a swarm of 4,070 earthquakes was recorded at Kamaʻehuakanaloa. At the time this was the most energetic earthquake swarm in Hawaii recorded history. The swarm altered of the seamount's summit; one section, Pele's Vents, collapsed entirely upon itself and formed the renamed Pele's Pit. The volcano has remained relatively active since the 1996 swarm and is monitored by the United States Geological Survey (USGS). The Hawaii Undersea Geological Observatory (HUGO) provided real time data on Kamaʻehuakanaloa between 1997 and 1998. Kamaʻehuakanaloa's last known eruption was in 1996, before the earthquake swarm of that summer.

The name Kamaʻehuakanaloa is a Hawaiian language word for "glowing child of Kanaloa", the god of the ocean. This name was found in two Hawaiian mele from the 19th and early twentieth centuries based on research at the Bishop Museum and was assigned by the Hawaiʻi Board on Geographic Names in 2021 and adopted by the U. S. Geological Survey. From 1955 to 2021 the seamount was called "Lōʻihi", the Hawaiian word for "long", describing its shape. The change to Kamaʻehuakanaloa was made in an effort to be more culturally appropriate given native Hawaiian traditions for naming.

Kamaʻehuakanaloa is a seamount, or underwater volcano, on the flank of Mauna Loa, the Earth's tallest shield volcano. It is the newest volcano produced by the Hawaiʻi hotspot in the extensive Hawaiian–Emperor seamount chain. The distance between the summit of the older Mauna Loa and the summit of Kamaʻehuakanaloa is about , which is, coincidentally, also the approximate diameter of the Hawaiʻi hotspot. Kamaʻehuakanaloa consists of a summit area with three pit craters, a long rift zone extending north from the summit, and a long rift zone extending south southeast from the summit. The thick crater walls of Pele's Pit – averaging in width, unusually thick for Hawaiian volcanic craters – suggest its craters have filled with lava multiple times in the past. Until 1970, Kamaʻehuakanaloa was thought to be an inactive volcano that had been transported to its current location by sea floor spreading. The seafloor under Hawaii is 80–100 million years old and was produced at the East Pacific Rise, an oceanic spreading center where new sea floor forms from magma that erupts from the mantle. New oceanic crust moves away from the spreading center. Over a period of 80–100 million years, the sea floor under Hawaii moved from the East Pacific Rise to its present location west, carrying ancient seamounts with it. When scientists investigated a series of earthquakes off Hawaii in 1970, they discovered that Kamaʻehuakanaloa was an active member of the Hawaiian–Emperor seamount chain. Kamaʻehuakanaloa is built on the seafloor with a slope of about five degrees. Its northern base on the flank of Mauna Loa is below sea level, but its southern base is a more substantial below the surface. Thus, the summit is above the seafloor as measured from the base of its north flank, but high when measured from the base of its southern flank. Continued volcanism is expected to eventually give birth to an island at Kamaʻehuakanaloa. It experiences frequent landslides; the growth of the volcano has destabilized its slopes, and extensive areas of debris inhabit the steep southeastern face. Similar deposits from other Hawaiian volcanoes indicate that landslide debris is an important product of the early development of Hawaiian volcanoes.

The vents lie below the surface, and range in temperature from 10 to over The vent fluids are characterized by a high concentration of (up to 17 mM) and Fe (Iron), but low in sulfide. Low oxygen and pH levels are important factors in supporting the high amounts of Fe (iron), one of the hallmark features of Kamaʻehuakanaloa. These characteristics make a perfect environment for iron oxidizing bacteria, called FeOB, to thrive in. An example of these species is Mariprofundus ferrooxydans, sole member of the class Zetaproteobacteria. The composition of the materials was similar to that of black smokers, that are a habitat of archaea extremophiles. Dissolution and oxidation of the mineral observed over the next two years suggests the sulfate is not easily preserved. A diverse community of microbial mats surround the vents and virtually cover Pele's Pit. The Hawaiʻi Undersea Research Laboratory (HURL), NOAA's Research Center for Hawaiʻi and the Western Pacific, monitors and researches the hydrothermal systems and studies the local community.

Marine life inhabiting the waters around Kamaʻehuakanaloa is not as diverse as life at other, less active seamounts. Fish found living near Kamaʻehuakanaloa include the Celebes monkfish (Sladenia remiger), and members of the cutthroat eel family, Synaphobranchidae. Invertebrates identified in the area include two species endemic to the hydrothermal vents, a bresiliid shrimp (Opaepele loihi) of the family Alvinocarididae (described in 1995), and a tube or pogonophoran worm. Dives conducted after the 1996 earthquake swarms were unable to find either the shrimp or the worm, and it is not known if there are lasting effects on these species. From 1982 to 1992, researchers in Hawaiʻi Undersea Research Laboratory submersibles photographed the fish of Kamaʻehuakanaloa Seamount, Johnston Atoll, and Cross Seamount at depths between A small number of species identified at Kamaʻehuakanaloa were newly recorded sightings in Hawaiʻi, including the tasseled coffinfish (Chaunax fimbriatus), and the Celebes monkfish.