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Lōʻihi Seamount 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 shield volcano on Earth. Lōʻihi, meaning "long" in Hawaiian, 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 Lōʻihi. Unlike most active volcanoes in the Pacific Ocean that make up the active plate margins on the Pacific Ring of Fire, Lōʻihi 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, Lōʻihi is the only Hawaiian volcano in the deep submarine preshield stage of development.
The Northwestern Hawaiian Islands or Leeward Islands are the small islands and atolls in the Hawaiian island chain located northwest of the islands of Kauai and Niihau. Politically, they are all part of Honolulu County in the U.S. state of Hawaii, except Midway Atoll, which is a territory distinct from the State of Hawaii, and grouped as one of the United States Minor Outlying Islands. The United States Census Bureau defines this area, except Midway, as Census Tract 114.98 of Honolulu County. Its total land area is 3.1075 square miles (8.048 km2). All the islands except Nihoa are north of the Tropic of Cancer, making them the only islands in Hawaii that lie outside the tropics.
The Hawaiian–Emperor seamount chain is a mostly undersea mountain range in the Pacific Ocean that reaches above sea level in Hawaii. It is composed of the Hawaiian ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor Seamounts: together they form a vast underwater mountain region of islands and intervening seamounts, atolls, shallows, banks and reefs along a line trending southeast to northwest beneath the northern Pacific Ocean. The seamount chain, containing over 80 identified undersea volcanoes, stretches about 6,200 km (3,900 mi) from the Aleutian Trench in the far northwest Pacific to the Lōʻihi Seamount, the youngest volcano in the chain, which lies about 35 kilometres (22 mi) southeast of the Island of Hawaiʻi.
The fifteen volcanoes that make up the eight principal islands of Hawaii are the youngest in a chain of more than 129 volcanoes that stretch 5,800 kilometres (3,600 mi) across the North Pacific Ocean, called the Hawaiian–Emperor seamount chain. Hawaiʻi's volcanoes rise an average of 4,600 metres (15,000 ft) to reach sea level from their base. The largest, Mauna Loa, is 4,169 metres (13,678 ft) high. As shield volcanoes, they are built by accumulated lava flows, growing a few meters or feet at a time to form a broad and gently sloping shape.
In geology, the places known as hotspots or hot spots are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Examples include the Hawaii, Iceland and Yellowstone hotspots. A hotspot's position on the Earth's surface is independent of tectonic plate boundaries, and so hotspots may create a chain of volcanoes as the plates move above them.
Meiji Seamount, named after Emperor Meiji, the 122nd Emperor of Japan, is the oldest seamount in the Hawaiian-Emperor seamount chain, with an estimated age of 82 million years. It lies at the northernmost end of the chain, and is perched at the outer slope of the Kuril–Kamchatka Trench. Like the rest of the Emperor seamounts, it was formed by the Hawaii hotspot volcanism, grew to become an island, and has since subsided to below sea level, all while being carried first north and now northwest by the motion of the Pacific Plate. Meiji Seamount is thus an example of a particular type of seamount known as a guyot, and some publications refer to it as Meiji Guyot.
The Hawai’i hotspot is a volcanic hotspot located near the namesake Hawaiian Islands, in the northern Pacific Ocean. One of the best known and intensively studied hotspots in the world, the Hawaii plume is responsible for the creation of the Hawaiian–Emperor seamount chain, a 6,200-kilometer (3,900 mi) mostly undersea volcanic mountain range. Four of these volcanoes are active, two are dormant; more than 123 are extinct, most now preserved as atolls or seamounts. The chain extends from south of the island of Hawaiʻi to the edge of the Aleutian Trench, near the eastern coast of Russia.
Detroit Seamount, which was formed around 76 million years ago, is one of the oldest seamounts of the Hawaiian-Emperor seamount chain. It lies near the northernmost end of the chain and is south of Aleutian Islands, at 51°28.80′N167°36′E It is a seamount in the chain, located north of the hinge of the "V" in the image at right.
Daikakuji Seamount is a seamount and the southwesternmost volcanic feature in the Hawaiian Emperor chain bend area.
Koko Guyot is a 48.1-million-year-old guyot, a type of underwater volcano with a flat top, which lies near the southern end of the Emperor seamounts, about 200 km (124 mi) north of the "bend" in the volcanic Hawaiian-Emperor seamount chain. Pillow lava has been sampled on the north west flank of Koko Seamount, and the oldest dated lava is 40 million years old. Seismic studies indicate that it is built on a 9 km (6 mi) thick portion of the Pacific Plate. The oldest rock from the north side of Koko Seamount is dated at 52.6 and the south side of Koko at 50.4 million years ago. To the southeast of the bend is Kimmei Seamount at 47.9 million years ago and southeast of it, Daikakuji at 46.7.
Ōjin Seamount, also called Ōjin Guyot, named after Emperor Ōjin, 15th Emperor of Japan, is a guyot of the Hawaiian-Emperor seamount chain in the Pacific Ocean. It erupted 55 million years ago.
Nintoku Seamount or Nintoku Guyot is a seamount and guyot in the Hawaiian-Emperor seamount chain. It is a large, irregularly shaped volcano that last erupted 66 million years ago. Three lava flows have been sampled at Nintoku Seamount; the flows are almost all alkalic (subaerial) lava. It is 56.2 million years old.
Yomei Seamount is a seamount of the Hawaiian-Emperor seamount chain in the northern Pacific Ocean.
Jingū Seamount, also called Jingū Guyot, is a guyot of the Hawaiian-Emperor seamount chain in the Pacific Ocean. It erupted 55 million years ago. The seamount is elongated in structure, running north–south, and has an oval shaped crater in the center, which is evidence of collapse when above sea level.
Suiko Seamount, also called Suiko Guyot, is a guyot of the Hawaiian-Emperor seamount chain in the Pacific Ocean.
Colahan Seamount is a seamount lying within the Hawaiian-Emperor seamount chain in the northern Pacific Ocean. It erupted 37-40 million years ago.
Abbott Seamount is a seamount lying within the Hawaiian-Emperor seamount chain in the northern Pacific Ocean. It erupted 36-40 million years ago.
Kanmu Seamount is a seamount lying within the Hawaiian-Emperor seamount chain in the Pacific Ocean. The last eruption of Kanmu Seamount is unknown.
Musicians Seamounts are a chain of seamounts in the Pacific Ocean, north of the Hawaiian Ridge. There are about 65 seamounts, some of which are named after musicians. These seamounts exist in two chains, one of which has been attributed to a probably now-extinct hotspot called the Euterpe hotspot. Others may have formed in response to plate tectonics associated with the boundary between the Pacific Plate and the former Farallon Plate.
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Coordinates: 35°00′N171°40′E / 35.000°N 171.667°E
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