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{{refimprove|date=March 2023}}
{{short description| Effusive volcanic eruption}} {{short description| Effusive volcanic eruption}}
]; 2, ]; 3, ]; 4, ]; 5, ]; 6, ]; 7, layers of lava and ash; 8, ]; 9, ]; 10, ] conduit; 11, ]; 12, ]]] ]; 2, ]; 3, ]; 4, ]; 5, ]; 6, ]; 7, layers of lava and ash; 8, ]; 9, ]; 10, ] conduit; 11, ]; 12, ]]]
A '''Hawaiian eruption''' is a ] where ] flows from the vent in a relatively gentle, low level eruption; it is so named because it is characteristic of ]. Typically they are ]s, with ]ic magmas of low ], low content of gases, and high temperature at the vent. Very small amounts of ] are produced. This type of eruption occurs most often at ] volcanoes such as ] on Hawaii's big island and ], though it can occur near subduction zones (e.g. ] in ], ]) and ] zones. A '''Hawaiian eruption''' is a ] where ] flows from the vent in a relatively gentle, low level eruption; it is so named because it is characteristic of ]. Typically they are ]s, with ]ic magmas of low ], low content of gases, and high temperature at the vent. Very small amounts of ] are produced. This type of eruption occurs most often at ] volcanoes such as ] on Hawaii's big island and ], though it can occur near subduction zones (e.g. ] in ]) and ] zones.
Hawaiian eruptions may occur along ]s, such as during the eruption of ] in 1950, or at a central vent, such as during the 1959 eruption in ] Crater, which created a lava fountain 580 meters (1,900 ft) high and formed a 38-meter cone named Pu{{okina}}u Pua{{okina}}i. In fissure-type eruptions, lava spurts from a fissure on the volcano's ] and feeds lava streams that flow downslope. In central-vent eruptions, a fountain of lava can spurt to a height of 300 meters or more (heights of 1600 meters were reported for the 1986 eruption of ] on ], ]). Hawaiian eruptions may occur along ]s, such as during the eruption of ] in 1950, or at a central vent, such as during the 1959 eruption in ] Crater, which created a ] 580 meters (1,900 ft) high and formed a 38-meter cone named Pu{{okina}}u Pua{{okina}}i. In fissure-type eruptions, lava spurts from a fissure on the volcano's ] and feeds lava streams that flow downslope. In central-vent eruptions, a fountain of lava can spurt to a height of 300 meters or more (heights of 1600 meters were reported for the 1986 eruption of ] on ], ]).


Hawaiian eruptions usually start by the formation of a crack in the ground from which a curtain of incandescent ] or several closely spaced magma fountains appear. The lava can overflow the fissure and form {{okina}}a{{okina}}ā or pāhoehoe style of flows. When such an eruption from a central cone is protracted, it can form lightly sloped ]es, for example Mauna Loa or ] in ]. Hawaiian eruptions usually start by the formation of a crack in the ground from which a curtain of incandescent lava or several closely spaced lava fountains appear. The lava can overflow the fissure and form {{okina}}a{{okina}}ā or pāhoehoe style of flows. When such an eruption from a central cone is protracted, it can form lightly sloped ]es, for example Mauna Loa or ] in ].


== Petrology of Hawaiian basalts == == Petrology of basalts in Hawaii ==


The key factors in generating a Hawaiian eruption are basaltic magma and a low percentage of dissolved water (less than one percent). The lower the water content, the more peaceful is the resulting flow. Almost all lava that comes from Hawaiian volcanoes is ] in composition. Hawaiian basalts that make up almost all of the islands are ]. These rocks are similar but not identical to those that are produced at ocean ridges. Basalt relatively richer in sodium and potassium (more alkaline) has erupted at the undersea volcano of ] (formerly Lō{{okina}}ihi) at the extreme southeastern end of the volcanic chain, and these rocks may be typical of early stages in the "evolution" of all Hawaiian islands. In the late stages of eruption of individual volcanoes, more alkaline basalt also was erupted, and in the very late stages after a period of erosion, rocks of unusual composition such as ] were produced in very small amounts. These variations in magma composition have been investigated in great detail, in part to try to understand how ]s may work. The key factors in generating a Hawaiian eruption are basaltic magma and a low percentage of dissolved water (less than one percent). The lower the water content, the more peaceful is the resulting flow. Almost all lava that comes from Hawaiian volcanoes is ] in composition. Hawaiian basalts that make up almost all of the islands are ]. These rocks are similar but not identical to those that are produced at ocean ridges. Basalt relatively richer in sodium and potassium (more alkaline) has erupted at the undersea volcano of ] (formerly Lō{{okina}}ihi) at the extreme southeastern end of the volcanic chain, and these rocks may be typical of early stages in the "evolution" of all Hawaiian islands. In the late stages of eruption of individual volcanoes, more alkaline basalt also was erupted, and in the very late stages after a period of erosion, rocks of unusual composition such as ] were produced in very small amounts. These variations in magma composition have been investigated in great detail, in part to try to understand how ]s may work.
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Hawaiian eruptions are considered less dangerous than other types of volcanic eruptions because they produce little ash and lava flows are generally slow-moving. However, they can still cause injuries or deaths. Hawaiian eruptions are considered less dangerous than other types of volcanic eruptions because they produce little ash and lava flows are generally slow-moving. However, they can still cause injuries or deaths.


In 1993, a photographer attempting to take pictures of a lava ocean entry died, and several tourists were injured, when a ] collapsed. In 2000, two people were found dead near a lava ocean entry from Kīlauea, likely killed by ].<ref name="sprowl">{{cite journal |last1=Sprowl |first1=GM |title=Hazards of Hawai'i Volcanoes National Park. |journal=Hawai'i Journal of Medicine & Public Health |date=November 2014 |volume=73 |issue=11 Suppl 2 |pages=17–20 |pmid=25478297 |pmc=4244893 }}</ref> ] emissions can also be fatal, especially to people suffering from respiratory ailments.<ref name="sprowl"/> A Hawaiian eruption broke a man's leg, and in 2018, 23 people on a tour boat were injured by a steam explosion and ] at a lava ocean entry.<ref>{{Cite magazine|url=http://time.com/5340313/lava-volcano-hawaii-tour-boat/|archive-url=https://web.archive.org/web/20180717194312/http://time.com/5340313/lava-volcano-hawaii-tour-boat/|url-status=dead|archive-date=July 17, 2018|title=23 Hurt After Lava From Hawaii Volcano Flies Through Roof of Tour Boat|magazine=Time|language=en|access-date=2018-07-17}}</ref> In 1993, a photographer attempting to take pictures of a lava ocean entry died, and several tourists were injured, when a ] collapsed. In 2000, two people were found dead near a lava ocean entry from Kīlauea, likely killed by ].<ref name="sprowl">{{cite journal |last1=Sprowl |first1=GM |title=Hazards of Hawai'i Volcanoes National Park. |journal=Hawai'i Journal of Medicine & Public Health |date=November 2014 |volume=73 |issue=11 Suppl 2 |pages=17–20 |pmid=25478297 |pmc=4244893 }}</ref> ] emissions can also be fatal, especially to people suffering from respiratory ailments.<ref name="sprowl"/> In 2018, 23 people on a tour boat were injured by a steam explosion and a ] at a lava ocean entry.<ref>{{Cite magazine|url=http://time.com/5340313/lava-volcano-hawaii-tour-boat/|archive-url=https://web.archive.org/web/20180717194312/http://time.com/5340313/lava-volcano-hawaii-tour-boat/|url-status=dead|archive-date=July 17, 2018|title=23 Hurt After Lava From Hawaii Volcano Flies Through Roof of Tour Boat|magazine=Time|language=en|access-date=2018-07-17}}</ref>


==See also== ==See also==
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Effusive volcanic eruption
Hawaiian eruption: 1, ash plume; 2, lava fountain; 3, crater; 4, lava lake; 5, fumarole; 6, lava flow; 7, layers of lava and ash; 8, stratum; 9, sill; 10, magma conduit; 11, magma chamber; 12, dike

A Hawaiian eruption is a type of volcanic eruption where lava flows from the vent in a relatively gentle, low level eruption; it is so named because it is characteristic of Hawaiian volcanoes. Typically they are effusive eruptions, with basaltic magmas of low viscosity, low content of gases, and high temperature at the vent. Very small amounts of volcanic ash are produced. This type of eruption occurs most often at hotspot volcanoes such as Kīlauea on Hawaii's big island and in Iceland, though it can occur near subduction zones (e.g. Medicine Lake Volcano in California) and rift zones. Hawaiian eruptions may occur along fissure vents, such as during the eruption of Mauna Loa in 1950, or at a central vent, such as during the 1959 eruption in Kīlauea Iki Crater, which created a lava fountain 580 meters (1,900 ft) high and formed a 38-meter cone named Puʻu Puaʻi. In fissure-type eruptions, lava spurts from a fissure on the volcano's rift zone and feeds lava streams that flow downslope. In central-vent eruptions, a fountain of lava can spurt to a height of 300 meters or more (heights of 1600 meters were reported for the 1986 eruption of Mount Mihara on Izu Ōshima, Japan).

Hawaiian eruptions usually start by the formation of a crack in the ground from which a curtain of incandescent lava or several closely spaced lava fountains appear. The lava can overflow the fissure and form ʻaʻā or pāhoehoe style of flows. When such an eruption from a central cone is protracted, it can form lightly sloped shield volcanoes, for example Mauna Loa or Skjaldbreiður in Iceland.

Petrology of basalts in Hawaii

The key factors in generating a Hawaiian eruption are basaltic magma and a low percentage of dissolved water (less than one percent). The lower the water content, the more peaceful is the resulting flow. Almost all lava that comes from Hawaiian volcanoes is basalt in composition. Hawaiian basalts that make up almost all of the islands are tholeiite. These rocks are similar but not identical to those that are produced at ocean ridges. Basalt relatively richer in sodium and potassium (more alkaline) has erupted at the undersea volcano of Kamaʻehuakanaloa (formerly Lōʻihi) at the extreme southeastern end of the volcanic chain, and these rocks may be typical of early stages in the "evolution" of all Hawaiian islands. In the late stages of eruption of individual volcanoes, more alkaline basalt also was erupted, and in the very late stages after a period of erosion, rocks of unusual composition such as nephelinite were produced in very small amounts. These variations in magma composition have been investigated in great detail, in part to try to understand how mantle plumes may work.

Safety

Hawaiian eruptions are considered less dangerous than other types of volcanic eruptions because they produce little ash and lava flows are generally slow-moving. However, they can still cause injuries or deaths.

In 1993, a photographer attempting to take pictures of a lava ocean entry died, and several tourists were injured, when a lava bench collapsed. In 2000, two people were found dead near a lava ocean entry from Kīlauea, likely killed by laze. Sulfur dioxide emissions can also be fatal, especially to people suffering from respiratory ailments. In 2018, 23 people on a tour boat were injured by a steam explosion and a lava bomb at a lava ocean entry.

See also

Notes

  1. ^ Sprowl, GM (November 2014). "Hazards of Hawai'i Volcanoes National Park". Hawai'i Journal of Medicine & Public Health. 73 (11 Suppl 2): 17–20. PMC 4244893. PMID 25478297.
  2. "23 Hurt After Lava From Hawaii Volcano Flies Through Roof of Tour Boat". Time. Archived from the original on July 17, 2018. Retrieved 2018-07-17.

References

  • Casadevall, T.J., ed. (1995). Volcanic Ash and Aviation Safety: Proceedings of the First International Symposium on Volcanic Ash and Aviation Safety. DIANE Publishing. p. 437. ISBN 978-0-7881-1650-6.
Hawaiian volcanism topics (list)
Windward
Isles
South Arch volcanic field
Kamaʻehuakanaloa
Māhukona
Hawaiʻi
Kīlauea (Kīlauea Iki, Pauahi Crater, Puʻu ʻŌʻō, Mauna Ulu)
Mauna Loa
Hualālai
Mauna Kea
Kohala
Kahoʻolawe
Kauaʻi
Kaʻula
Lānaʻi
Maui
Haleakalā
West Maui
Molokaʻi
Penguin Bank
West Molokai Volcano
East Molokai Volcano
Niʻihau
Oʻahu
Honolulu
Kaʻena
Koʻolau
North Arch volcanic field
Waiʻanae
Scheme of a Hawaiian eruption
Leeward
Isles
Emperor
Seamounts
Notable eruptions
and vents
Topics
Types of volcanic eruptions
Magmatic
Phreatomagmatic
Phreatic
Other classifications
Categories: