Kamaʻehuakanaloa Seamount (previously known as Lōʻihi) is an active submarine volcano about 22 mi (35 km) off the southeast coast of the island of Hawaii. The top of the seamount is about 3,200 ft (975 m) below sea level. This seamount is on the flank of Mauna Loa, the largest subaerial active shield volcano on Earth. Kamaʻehuakanaloa is the newest volcano in the Hawaiian–Emperor seamount chain, a string of volcanoes that stretches about 3,900 mi (6,200 km) 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 10,000 ft (3,000 m) above the seafloor, making it taller than Mount St. Helens was before its catastrophic 1980 eruption. A diverse microbial community resides around Kamaʻehuakanaloa's 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 4 to 5 sq mi (10 to 13 km2) 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.
Naming 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.
Characteristics
Geology
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 50 mi (80 km), which is, coincidentally, also the approximate diameter of the Hawaiʻi hotspot. Kamaʻehuakanaloa consists of a summit area with three pit craters, a 7 mi (11 km) long rift zone extending north from the summit, and a 12 mi (19 km) long rift zone extending south-southeast from the summit. The summit's pit craters are named West Pit, East Pit, and Pele's Pit. Pele's Pit is the youngest of this group and is located at the southern part of the summit. The walls of Pele's Pit stand 700 ft (200 m) high and were formed in July 1996 when its predecessor, Pele's Vent, a hydrothermal field near Kamaʻehuakanaloa summit, collapsed into a large depression. The thick crater walls of Pele's Pit – averaging 70 ft (20 m) in width, unusually thick for Hawaiian volcanic craters – suggest its craters have filled with lava multiple times in the past.
Kamaʻehuakanaloa's north–south trending rift zones form a distinctive elongated shape, from which the volcano's earlier Hawaiian name "Lōʻihi," meaning "long", derives. The north rift zone consists of a longer western portion and a shorter eastern rift zone. Observations show that both the north and south rift zones lack sediment cover, indicating recent activity. A bulge in the western part of the north rift zone contains three 200–260 ft (60–80 m) cone-shaped prominences. 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 3,700 mi (6,000 km) 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 2,100 yd (1,900 m) below sea level, but its southern base is a more substantial 15,600 ft (4,755 m) below the surface. Thus, the summit is 3,054 ft (931 m) above the seafloor as measured from the base of its north flank, but 12,421 ft (3,786 m) high when measured from the base of its southern flank. Kamaʻehuakanaloa is following the pattern of development that is characteristic of all Hawaiian volcanoes. Geochemical evidence from Kamaʻehuakanaloa's lavas indicates that Kamaʻehuakanaloa is in transition between the preshield and shield volcano stage, providing clues to the early development of Hawaiian volcanoes. In the preshield stage, Hawaiian volcanoes have steeper sides and a lower level of activity, producing an alkali basalt lava. 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. Kamaʻehuakanaloa is predicted to rise above the surface in 10,000 to 100,000 years.
Age and growth
… excerpt ends here. Continue reading the full article.
