Topic: Volcanoes

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๐Ÿ”— Year Without a Summer

๐Ÿ”— Volcanoes ๐Ÿ”— Meteorology

The year 1816 is known as the Year Without a Summer (also the Poverty Year and Eighteen Hundred and Froze To Death) because of severe climate abnormalities that caused average global temperatures to decrease by 0.4โ€“0.7ย ยฐC (0.72โ€“1.26ย ยฐF). This resulted in major food shortages across the Northern Hemisphere.

Evidence suggests that the anomaly was predominantly a volcanic winter event caused by the massive 1815 eruption of Mount Tambora in April in the Dutch East Indies (now Indonesia). This eruption was the largest eruption in at least 1,300 years (after the hypothesized eruption causing the extreme weather events of 535โ€“536), and perhaps exacerbated by the 1814 eruption of Mayon in the Philippines.

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๐Ÿ”— Dallol

๐Ÿ”— Volcanoes ๐Ÿ”— Biology ๐Ÿ”— Africa ๐Ÿ”— Geology ๐Ÿ”— Ethiopia

Dallol is a unique, terrestrial hydrothermal system around a cinder cone volcano in the Danakil Depression, northeast of the Erta Ale Range in Ethiopia. It is known for its unearthly colors and mineral patterns, and the very acidic fluids that discharge from its hydrothermal springs.

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๐Ÿ”— Toba catastrophe theory

๐Ÿ”— Volcanoes ๐Ÿ”— Disaster management ๐Ÿ”— Geology ๐Ÿ”— Indonesia

The Toba supereruption was a supervolcanic eruption that occurred about 75,000 years ago at the site of present-day Lake Toba in Sumatra, Indonesia. It is one of the Earth's largest known eruptions. The Toba catastrophe theory holds that this event caused a global volcanic winter of six to ten years and possibly a 1,000-year-long cooling episode.

In 1993, science journalist Ann Gibbons posited that a population bottleneck occurred in human evolution about 70,000 years ago, and she suggested that this was caused by the eruption. Geologist Michael R. Rampino of New York University and volcanologist Stephen Self of the University of Hawaii at Manoa support her suggestion. In 1998, the bottleneck theory was further developed by anthropologist Stanley H. Ambrose of the University of Illinois at Urbanaโ€“Champaign. Both the link and global winter theories are controversial. The Toba event is the most closely studied supereruption.

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๐Ÿ”— Lunar Lava Tube

๐Ÿ”— Volcanoes ๐Ÿ”— Astronomy ๐Ÿ”— Solar System ๐Ÿ”— Solar System/Moon

Lunar lava tubes are lava tubes on the Moon formed during the eruption of basaltic lava flows. When the surface of a lava flow cools, it hardens and the lava can channel beneath the surface in a tube-shaped passage. Once the flow of lava diminishes, the tube may drain, forming a hollow void. Lunar lava tubes are formed on sloped surfaces that range in angle from 0.4ยฐ to 6.5ยฐ. These tubes may be as wide as 500 metres (1,600ย ft) before they become unstable against gravitational collapse. However, stable tubes may still be disrupted by seismic events or meteoroid bombardment.

The existence of a lava tube is sometimes revealed by the presence of a "skylight", a place in which the roof of the tube has collapsed, leaving a circular hole that can be observed by lunar orbiters.

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๐Ÿ”— Larry Ellison Owns 98% of Lanai Island, Hawaii

๐Ÿ”— Volcanoes ๐Ÿ”— Islands ๐Ÿ”— Hawaii

Lanai (Hawaiian: Lฤnaสปi, Hawaiian: [laหหˆnษส”i, naหหˆnษส”i], lษ™-NY, lah-NAH-ee, also US: lah-NY, lษ™-NAH-ee,) is the sixth-largest of the Hawaiian Islands and the smallest publicly accessible inhabited island in the chain. It is colloquially known as the Pineapple Island because of its past as an island-wide pineapple plantation. The island's only settlement of note is the small town of Lanai City. As of 2012, the island is 98% owned by Larry Ellison, cofounder and chairman of Oracle Corporation; the remaining 2% is owned by the state of Hawaii or individual homeowners.

Lanai is a roughly apostrophe-shaped island with a width of 18 miles (29ย km) in the longest direction. The land area is 140.5 square miles (364ย km2), making it the 43rd largest island in the United States. It is separated from the island of Molokaสปi by the Kalohi Channel to the north, and from Maui by the Auสปau Channel to the east. The United States Census Bureau defines Lanai as Census Tract 316 of Maui County. Its total population rose to 3,367 as of the 2020 United States census, up from 3,193 as of the 2000 census and 3,131 as of the 2010 census. As visible via satellite imagery, many of the island's landmarks are accessible only by dirt roads that require a four-wheel drive vehicle due to the lack of paved roadways.

There is one school, Lanai High and Elementary School, serving the entire island from kindergarten through 12th grade. There is also one hospital, Lanai Community Hospital, with 24 beds, and a community health center providing primary care, dental, behavioral health and selected specialty services in Lanai City. There are no traffic lights on the island.

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๐Ÿ”— 1808/1809 Mystery Eruption

๐Ÿ”— Climate change ๐Ÿ”— Environment ๐Ÿ”— Volcanoes

The 1808 mystery eruption was a large volcanic eruption conjectured to have taken place in late 1808, possibly in the southwest Pacific. A VEI-6 eruption, comparable to the 1883 eruption of Krakatoa, is suspected of having contributed to a period of global cooling that lasted for years, analogous to how the 1815 eruption of Mount Tambora (VEI-7) led to the Year Without a Summer in 1816.

Discussed on

๐Ÿ”— South Georgia and the South Sandwich Islands

๐Ÿ”— Volcanoes ๐Ÿ”— Islands ๐Ÿ”— British Overseas Territories ๐Ÿ”— Argentina ๐Ÿ”— South America/South Georgia and the South Sandwich Islands ๐Ÿ”— South America

South Georgia and the South Sandwich Islands (SGSSI) is a British Overseas Territory in the southern Atlantic Ocean. It is a remote and inhospitable collection of islands, consisting of South Georgia Island and a chain of smaller islands known as the South Sandwich Islands. South Georgia is 165 kilometres (103ย mi) long and 35 kilometres (22ย mi) wide and is by far the largest island in the territory. The South Sandwich Islands lie about 700 kilometres (430ย mi) southeast of South Georgia. The territory's total land area is 3,903ย km2 (1,507ย sqย mi). The Falkland Islands are about 1,300 kilometres (810ย mi) west from its nearest point.

No permanent native population lives in the South Sandwich Islands, and a very small non-permanent population resides on South Georgia. There are no scheduled passenger flights or ferries to or from the territory, although visits by cruise liners to South Georgia are increasingly popular, with several thousand visitors each summer.

The United Kingdom claimed sovereignty over South Georgia in 1775 and the South Sandwich Islands in 1908. The territory of "South Georgia and the South Sandwich Islands" was formed in 1985; previously, it had been governed as part of the Falkland Islands Dependencies. Argentina claimed South Georgia in 1927 and claimed the South Sandwich Islands in 1938.

Argentina maintained a naval station, Corbeta Uruguay, on Thule Island in the South Sandwich Islands from 1976 until 1982 when it was closed by the Royal Navy. The Argentine claim over South Georgia contributed to the 1982 Falklands War, during which Argentine forces briefly occupied the island. Argentina continues to claim sovereignty over South Georgia and the South Sandwich Islands.

Toothfish are vital to the islands' economy; as a result, Toothfish Day is celebrated on 4 September as a bank holiday in the territory.

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๐Ÿ”— Graham Island (Sicily)

๐Ÿ”— Volcanoes ๐Ÿ”— Islands ๐Ÿ”— Sicily ๐Ÿ”— Seamounts

Graham Island (also Graham Bank or Graham Shoal; Italian: Isola Ferdinandea) is a submerged volcanic island in the Mediterranean Sea. It was discovered when it last appeared on 1 August 1831 by Humphrey Fleming Senhouse, the captain of the first rate Royal Navy ship of the line St Vincent and named after Sir James Graham, the First Lord of the Admiralty. It was claimed by the United Kingdom. It forms part of the underwater volcano Empedocles, 30ย km (19ย mi) south of Sicily, and which is one of a number of submarine volcanoes known as the Campi Flegrei del Mar di Sicilia. Seamount eruptions have raised it above sea level several times before erosion submerged it again.

When it last rose above sea level after erupting in 1831, a four-way dispute over its sovereignty began, which was still unresolved when it disappeared beneath the waves again in early 1832. During its brief life, French geologist Constant Prรฉvost was on hand, accompanied by an artist, to witness it in July 1831; he named it รŽle Julia, for its July appearance, and reported in the Bulletin de la Sociรฉtรฉ Gรฉologique de France. Some observers at the time wondered if a chain of mountains would spring up, linking Sicily to Tunisia and thus upsetting the geopolitics of the region. It showed signs of volcanic activity in 2000 and 2002, forecasting a possible appearance; however, as of 2016 it remains 6ย m (20ย ft) under sea level.

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๐Ÿ”— Volcanic Winter

๐Ÿ”— Environment ๐Ÿ”— Volcanoes ๐Ÿ”— Geology ๐Ÿ”— Weather ๐Ÿ”— Weather/Non-tropical storms

A volcanic winter is a reduction in global temperatures caused by volcanic ash and droplets of sulfuric acid and water obscuring the Sun and raising Earth's albedo (increasing the reflection of solar radiation) after a large, particularly explosive volcanic eruption. Long-term cooling effects are primarily dependent upon injection of sulfur gases into the stratosphere where they undergo a series of reactions to create sulfuric acid which can nucleate and form aerosols. Volcanic stratospheric aerosols cool the surface by reflecting solar radiation and warm the stratosphere by absorbing terrestrial radiation. The variations in atmospheric warming and cooling result in changes in tropospheric and stratospheric circulation.