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The Hawaiian–Emperor seamount chain is a series of volcanoes and seamounts extending about 6,200 km (3,900 mi) across the Pacific Ocean.[n 1]
The chain was produced by the movement of the ocean crust over the Hawaiʻi hotspot, an upwelling of hot rock from the Earth's mantle.
As the oceanic crust moves the volcanoes farther away from their source of magma, their eruptions become less frequent and less powerful until they eventually cease to erupt altogether. At that point, erosion of the volcano and subsidence of the seafloor cause the volcano to gradually diminish.
As the volcano sinks and erodes, it first becomes an atoll island and then an atoll. Further subsidence causes the volcano to sink below the sea surface, becoming a seamount. Once a seamount is 600 metres or more under the surface, it is also classed as a guyot.[1] This list documents the most significant volcanoes in the chain, ordered by distance from the hotspot, but there are many others that have yet to be properly studied.
The chain can be divided into three subsections. The first, the main windward Hawaiian islands consist of the eight youngest and easternmost Hawaiian islands. This is the youngest part of the chain and includes volcanoes with ages ranging from 400,000 years[2] to 5.1 million years.[3] The island of Hawaiʻi comprises five volcanoes, of which two (Kilauea and Mauna Loa) are still active. Kamaʻehuakanaloa Seamount (formerly Lōʻihi) continues to grow offshore, and is the only known volcano in the chain in the submarine pre-shield stage.[1]
The second part of the chain is composed of the Northwestern Hawaiian Islands, collectively referred to as the Leeward isles, the constituents of which are between 7.2 and 27.7 million years old.[3] Erosion has long since overtaken volcanic activity at these islands, and most of them are atolls, atoll islands, and extinct islands. They contain many of the most northerly atolls in the world, including Kure Atoll, the northernmost atoll in the world.[4]
The oldest and most heavily eroded part of the chain are the Emperor seamounts, which are 39[5] to 85 million years old.[6]
The Emperor and Hawaiian chains are separated by a large L-shaped bend that causes the orientations of the chains to differ by about 60 degrees. This bend was long attributed to a relatively sudden change in the direction of plate motion, but research conducted in 2003 suggests that it was the movement of the hotspot itself that caused the bend.[7] The issue is still currently under debate.[8]
All of the volcanoes in this part of the chain have long since subsided below sea level, becoming seamounts and guyots (see also the seamount and guyot stages of Hawaiian volcanism). Many of the volcanoes are named after former emperors of Japan. The seamount chain extends to the West Pacific, and terminates at the Kuril–Kamchatka Trench, a subduction zone at the border of Russia.[9]
Hawaiian archipelago
| Name | Island | Last eruption | Coordinates | Age (years) | Notes |
|---|---|---|---|---|---|
| Kamaʻehuakanaloa Seamount (formerly Lōʻihi) | Seamount | 1996 (active)[2] | 18°55′N 155°16′W / 18.92°N 155.27°W | 400,000[2] | The seamount is a submarine volcano approximately 35 km (22 mi) southeast of Hawaiʻi. It may eventually breach sea level and become the newest Hawaiian island.[2] |
| Kīlauea | Big Island | 2021–ongoing (active)[10] | 19°25′N 155°17′W / 19.417°N 155.283°W | 300,000–600,000[11] | Kīlauea is considered one of the most active volcanoes on Earth.[12]
Kīlauea, was in near-continuous eruption on its East Rift Zone from January 3, 1983, to September 4, 2018, making it the longest-lived rift-zone eruption of the last six centuries.[13] |
| Mauna Loa | Big Island | 2022-ongoing (active)[14] | 19°28′46″N 155°36′10″W / 19.47944°N 155.60278°W | 700,000–1 million[15] | Largest subaerial volcano on Earth[14] |
| Hualālai | Big Island | 1800–1801 (active)[16] | 19°41′32″N 155°52′02″W / 19.69222°N 155.86722°W | > 300,000[16] | Lies on the western edge of the Big Island[16] |
| Mauna Kea | Big Island | 4460 BP (dormant) | 19°49′14″N 155°28′05″W / 19.82056°N 155.46806°W | ~1 million[17] | World's tallest mountain if below-sea elevation is counted[18] |
| Kohala | Big Island | 120,000 BP (extinct)[19] | 20°05′10″N 155°43′02″W / 20.08611°N 155.71722°W | ~ 120,000–1 million[19] | Oldest volcano that remains part of the island of Hawaiʻi[19] |
| Māhukona | Seamount | 470,000 BP (extinct) | 20°01′N 156°01′W / 20.017°N 156.017°W | K-Ar 298,000±25,000 and 310,000±31,000[20][n 2] | Submerged, having long since disappeared into the sea[21] |
| Haleakalā | Maui | between A.D. 1480 and 1600, oldest currently active volcano in the Hawaiian - Emperor seamount chain[22] | 20°42′35″N 156°15′12″W / 20.70972°N 156.25333°W | ~ 2 million[22] | Forms more than 75% of Maui[22] |
| West Maui | Maui | less than 320,000 BP (extinct) | 20°54′N 156°37′W / 20.900°N 156.617°W | K-Ar 1.32±0.04 million[3] | Very eroded shield volcano that makes up the western quarter of Maui |
| Kahoʻolawe | Kahoʻolawe | ~1 MYA | 20°33′N 156°36′W / 20.550°N 156.600°W | K-Ar > 1.03±0.18 million[3][23] | Smallest of the 8 principal Hawaiian islands;[19] uninhabited[24] |
| Lānaʻi | Lānaʻi | 1.2 MYA | 20°50′N 156°56′W / 20.833°N 156.933°W | K-Ar date of 1.28±0.04 million[3] | Sixth-largest island[25] The only town is Lānaʻi City, a small settlement. |
| East Molokai | Molokaʻi | 1.3 MYA | 21°7′N 156°51′W / 21.117°N 156.850°W | K-Ar 1.76±0.04 million[3] | The northern half of this volcano suffered a large collapse 1.5 million years ago.[26] Only the southern half remains above the sea today.[19] |
| West Molokaʻi | Molokaʻi | 1.76 MYA | 21°9′N 157°14′W / 21.150°N 157.233°W | K-Ar date of 1.9±0.06 million[3] | |
| Penguin Bank | Seamount | —
|
20°55′N 157°40′W / 20.917°N 157.667°W | ~ 2.2 million[27] | The seamount is a submarine volcano, southwest of Molokaʻi. The submarine volcano used to be part of Maui Nui, a prehistoric island made from seven shield volcanoes. |
| Koʻolau Range | Oʻahu | <32,000 BP (possibly dormant)[n 3] | 21°19′N 157°46′W / 21.317°N 157.767°W | 2.7 million[28] | A fragmented remnant of the eastern or windward shield volcano, which also suffered a large collapse sometime before the Molokaʻi collapse[26] |
| Waiʻanae Range | Oʻahu | ~2.5 MYA[29] | 21°30′N 158°09′W / 21.500°N 158.150°W | ~1.7–3.9 million; K-Ar 3.7±0.1 million[3][28][29] | The eroded remains of a shield volcano that comprised the western half of the island[29] |
| Kaʻena Ridge | Oʻahu | <3.0 MYA[30] | 21°42′N 158°22′W / 21.700°N 158.367°W[30] | ~3.5–4.9 million[30] | The eroded remains of a shield volcano west of Waiʻanae that has since subsided below sea level[30] |
| Kaʻula | Kaʻula | >2 MYA | 21°39′N 160°32′W / 21.650°N 160.533°W | K-Ar 4.0±0.2 million[3] | Tiny crescent-shaped barren island; uninhabited except for divers and fishermen[31] |
| Niʻihau | Niʻihau | 2 MYA | 21°54′N 160°10′W / 21.900°N 160.167°W | K-Ar 4.89±0.11 million[3][32] | Smallest inhabited island;[33] |
| Kauaʻi | Kauaʻi | 1.41 MYA[n 3] | 22°05′N 159°30′W / 22.083°N 159.500°W | K-Ar 5.1±0.2 million[3][34] | Oldest and fourth largest of the main islands, and home to Mount Waialeale, one of the wettest areas on Earth in terms of precipitation[35] |
Northwestern Hawaiian islands
| Name | Type | Coordinates | Age[36] | Notes |
|---|---|---|---|---|
| Unnamed seamount | Guyot | 22°42′N 161°02′W / 22.700°N 161.033°W | 5.1 to 7.2 million[n 4] | at a depth of 40 m (130 ft) below sea level |
| Nihoa | Extinct Island | 23°03′N 161°55′W / 23.050°N 161.917°W | K-Ar 7.2±0.3 million[3] | Small rocky island which supported a small population around 1000 CE; features over 80 cultural sites, including religious places, agricultural terraces, and burial caves[37] |
| Unnamed seamount | Guyot | 22°59′N 162°14′W / 22.983°N 162.233°W | 7.2 to 10.3 million[n 4] | at a depth of 10 m (33 ft) below sea level |
| Unnamed seamount | Guyot | 23°14′N 162°37′W / 23.233°N 162.617°W | 7.2 to 10.3 million[n 4] | at a depth of 229 m (751 ft) below sea level |
| Unnamed seamount | Guyot | 23°14′N 162°57′W / 23.233°N 162.950°W | 7.2 to 10.3 million[n 4] | at a depth of 5 m (16 ft) below sea level |
| Unnamed seamount | Guyot | 23°12′N 163°10′W / 23.200°N 163.167°W | 7.2 to 10.3 million[n 4] | at a depth of 44 m (144 ft) below sea level |
| Unnamed seamount | Guyot | 23°18′N 163°16′W / 23.300°N 163.267°W | 7.2 to 10.3 million[n 4] | at a depth of 413 m (1,355 ft) below sea level |
| Necker Island | Extinct Island | 23°34′35″N 164°42′0″W / 23.57639°N 164.70000°W | K-Ar 10.3±0.4 million[3] | Small deserted island with Hawaiian religious shrines and artifacts[38] |
| French Frigate Shoals | Atoll | 23°52′08″N 166°17′10″W / 23.8689°N 166.2860°W | 12 million[39] | Largest atoll in the northwestern Hawaiian islands[40] |
| East Brooks Bank | Guyot | 23°59′N 166°42′W / 23.983°N 166.700°W | 12 to 12.3 million[n 4] | at a depth of 51 m (167 ft) below sea level |
| Central Brooks Bank | Guyot | 24°07′N 166°49′W / 24.117°N 166.817°W | 12 to 12.3 million[n 4] | at a depth of 29 m (95 ft) below sea level |
| West Brooks Bank | Guyot | 24°12′N 166°57′W / 24.200°N 166.950°W | 12 to 12.3 million[n 4] | at a depth of 24 m (79 ft) below sea level |
| Saint Rogatien Bank | Guyot | 24°19′N 167°08′W / 24.317°N 167.133°W | 12 to 12.3 million[n 4] | at a depth of 20 m (66 ft) below sea level |
| Gardner Pinnacles | Atoll Island | 25°01′N 167°59′W / 25.017°N 167.983°W | K-Ar 12.3±1.0 million[3] | Two barren rock outcrops surrounded by a reef[41] |
| Raita Bank | Guyot | 25°33′N 169°27′W / 25.550°N 169.450°W | 12.3 to 19.9 million[n 4] | at a depth of 13 m (43 ft) below sea level |
| Maro Reef | Atoll | 25°25′N 170°35′W / 25.417°N 170.583°W | 12.3 to 19.9 million[n 4] | Largest coral reef of the northwestern Hawaiian islands[42] |
| Laysan | Atoll Island | 25°46′03″N 171°44′00″W / 25.7675°N 171.7334°W | K-Ar 19.9±0.3 million[3] | Originally named "Kauō" meaning egg, referring to its shape, and home to one of only five natural lakes in all of Hawaiʻi[43] |
| Unnamed seamount | Guyot | 25°22′N 172°03′W / 25.367°N 172.050°W | 19.9 to 20.6 million[n 4] | at a depth of 1 m (3.3 ft) below sea level |
| Northampton Seamount | Guyot | 25°30′N 172°24′W / 25.500°N 172.400°W | 19.9 to 20.6 million[n 4] | at a depth of 6 m (20 ft) below sea level |
| Unnamed seamount | Guyot | 25°39′N 172°56′W / 25.650°N 172.933°W | 19.9 to 20.6 million[n 4] | at a depth of 872 m (2,861 ft) below sea level |
| Pioneer Tablemount | Guyot | 25°59′N 173°24′W / 25.983°N 173.400°W | 19.9 to 20.6 million[n 4] | at a depth of 5 m (16 ft) below sea level |
| Lisianski Island | Atoll Island | 26°3′49″N 173°57′57″W / 26.06361°N 173.96583°W | 19.9 to 20.6 million[n 4] | A small island surrounded by a huge coral reef nearly the size of Oahu;[44] named after a captain in the Russian navy whose ship ran aground there in 1805[45] |
| Unnamed seamount | Guyot | 26°18′N 174°32′W / 26.300°N 174.533°W | 19.9 to 20.6 million[n 4] | at a depth of 67 m (220 ft) below sea level |
| Unnamed seamounts | Guyot | 26°56′N 175°36′W / 26.933°N 175.600°W | 19.9 to 20.6 million[n 4] | pair of guyots at a depth of 115 m (377 ft) and 1,207 m (3,960 ft) below sea level |
| Unnamed seamount | Guyot | 27°09′N 176°10′W / 27.150°N 176.167°W | 19.9 to 20.6 million[n 4] | at a depth of 1,233 m (4,045 ft) below sea level |
| Salmon Bank | Guyot | 26°56′N 176°25′W / 26.933°N 176.417°W | 19.9 to 20.6 million[n 4] | at a depth of 54 m (177 ft) below sea level |
| Pearl and Hermes Atoll | Atoll Island | 27°48′N 175°51′W / 27.800°N 175.850°W | K-Ar 20.6±2.7 million[3] | A collection of small, sandy islands, with a lagoon and coral reef; named after two whaling ships which were wrecked on the reef in 1822[46] |
| Unnamed seamount | Guyot | 28°05′N 176°54′W / 28.083°N 176.900°W | 20.6 to 27.7 million[n 4] | at a depth of 1,640 m (5,380 ft) below sea level |
| Ladd Seamount | Guyot | 28°31′45″N 176°40′00″W / 28.52917°N 176.66667°W | 20.6 to 27.7 million[n 4] | at a depth of 64 m (210 ft) below sea level |
| Midway Atoll | Atoll Island | 28°12′N 177°21′W / 28.200°N 177.350°W | K-Ar 27.7±0.6 million[3] | Consists of a ring-shaped barrier reef and two large islets; named "Midway" because of its strategic location in the center of the Pacific Ocean, and was the site of a key battle during World War II[47] |
| Nero Seamount | Guyot | 27°57′55″N 177°57′50″W / 27.96528°N 177.96389°W | 27.7 to 38.7 million[n 4] | at a depth of 67 m (220 ft) below sea level |
| Kure Atoll | Atoll | 28°25′N 178°20′W / 28.417°N 178.333°W | 27.7 to 38.7 million[n 4] | Northernmost coral atoll in the world[4] |