Thursday, May 20, 2010

10 Amazing Active Volcanoes

 

Volcanoes are in the news and not in a good way, but Iceland’s tongue-twistingly named, travel-disrupting Eyjafjallajökull volcano is just doing what volcanoes do: erupt. It’s not alone, either. Around the world at any given moment, dozens of volcanoes are smoking, shaking and stirring up their neighborhoods. Here are 10 of the most active.


Kilauea, Hawaii, USA

Kilauea, Hawaii, USA

Kilauea Volcano on the island of Hawaii (the Big Island) is widely considered to be the most active volcano on Earth. Over the course of its most recent eruption which began in January of 1983, the volcano has expelled enough lava to pave a road around the planet three times over.

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If not for its brilliant orange lava fountains and slow-flowing rivers of molten rock, Kilauea wouldn’t be much to look at: though the summit is 4,091 feet (1,247m) above sea level, the gently sloping shield volcano is dwarfed by neighboring 13,677 ft (4,169m) high Mauna Loa… for the present, at least.

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Kilauea’s name means “spewing” in the Hawaiian language; an indication that the volcano has been erupting long before England’s Captain Cook discovered the Hawaiian Islands in the late 18th century. One relic of those days are the “1790 Footprints” preserved in hardened lava from an explosive eruption of Kilauea. The footprints are said to have been left by up to 80 warriors from a dissident Hawaiian faction who died in a pyroclastic flow from Kilauea.

Etna, Italy

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Mount Etna, on the Italian island of Sicily, has been erupting more or less continuously for the past 2,000 years though its overall history stretches back approximately 300,000 years. Though somewhat less famous (or infamous) than neighboring Mount Vesuvius, Mount Etna greatly outclasses the latter peak as it rises 2.5 times its height. In addition, most of Etna’s more spectacular eruptions and associated geological events occurred in prehistory. The volcano erupted in every year from 200 through 2008 and its recent eruption occurred in April of 2010.

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Volcanoes occasionally belch giant smoke rings into the sky, a rare and curious phenomenon that can last up to 15 minutes and range in size up to 600 feet across! Mount Etna has blown volcanic smoke rings on a number of occasions; some of those that occurred during the 2000 eruption have been documented photographically.

Nyamuragira, Democratic Republic of Congo

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Mount Nyamuragira is an active volcano located in the Virunga Mountains of the Democratic Republic of the Congo. Although it has erupted more than 30 times since explorers of European origin began documenting the mountain in the 1880s, recent eruptions have caused ever greater concern as the surrounding area has become heavily populated. As well, the Virunga range is one of the last remaining sanctuaries for threatened great apes including majestic Mountain Gorillas.

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Mount Nyamuragira brought in the new year with an eruption: On January 2, 2010, lava began to flow from the main crater eventually reaching a distance of 1,640 feet (500m) downslope to the south and southwest. Mount Nyamuragira often exudes a particularly thin and fast-moving type of lava that makes any necessary evacuations hurried and often disorganized affairs.

Sakurajima, Japan

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The Sakurajima volcano is located on what was formerly an island in southern Japan’s Kagoshima Bay. The island is now connected to the mainland via a low-lying peninsula created by lava flows during the mountain’s immense eruption of 1914. Sakurajima stands 3,665 feet (1,117m) above sea level and has been erupting more or less continuously since 1955.

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Sakurajima is a successor volcano that exudes and erupts magma from the huge subterranean chamber beneath the Aira Caldera. This 12 mile (20 km) wide caldera was created approximately 22,000 years ago in a massive eruption that sent ash and tephra hundreds of miles in every direction. Should Sakurajima follow the same path to destruction, millions of people will find themselves at extreme risk.

Erebus, Antarctica

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The world’s most southerly active volcano, Mount Erebus has been erupting since 1972 though the eruptions have varied greatly in intensity. The 12,448 ft (3,794m) snow-covered stratovolcano is covered with snow but harbors in its crater a red hot, long-lasting lava lake that can be seen from space.

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Mount Erebus regularly subjects its frigid environs to a blast of geothermal activity, resulting in ethereal ice caves and horn-like fumaroles carved out of its icy coat by scalding steam. Though considered to be in a state of eruption, Mount Erebus behaves rather calmly (as volcanoes go) and has been extensively studied by volcanologists based at nearby McMurdo Station (USA) and Scott Base (NZ).

Chaitén, Chile

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The Chaitén volcano in southern Chile began erupting on May 2 of 2008, an event that caught scientists by surprise as the mountain’s last eruption was estimated to have occurred about 9,500 years ago. Though the mountain is still in an eruptive state, the initial stages were marked by the expulsion of voluminous ash clouds shot through by incandescent bolts of lightning.

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Within 24 hours of the eruption’s inception, a huge plume of ash had risen tens of thousands of feet into the sky, there to be blown to the southeast by upper level winds. The ash plume was photographed from orbiting satellites and can be seen above, stretching completely across the width of Argentina and far into the South Atlantic Ocean.

Anak Krakatau, Indonesia

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Anak Krakatau (“child of Krakatoa”) may not be especially large but note the name – it carries within it the seeds of future disaster. Though the famed 1883 explosive eruption of its parent peak (Krakatoa, east of Java) caused the deaths of roughly 36,000 people, a similar event today would be unfathomably worse due to exceptional population growth over the past century.

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As Anak Krakatau grows larger – it’s been adding approximately 5 inches (13cm) per week to its height since 1955 – it also grows more dangerous. The volcano’s current eruptive phase began in April of 2008 and is ongoing.

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nak Krakatau first poked its summit above the surface of the Sunda Strait between the Indonesian islands of Java and Sumatra in August of 1930 and by 2005 had reached a height of 985 feet (300m)… when Krakatoa exploded with the force of a 200 megaton atomic bomb in 1883 it was 2,667 ft (813m) high.

Tungurahua, Ecuador

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Tungurahua is one of the world’s tallest volcanoes, soaring 16,480 ft (5,023 m) into the thin Andean air above the South American nation of Ecuador. Those figures will likely need to be revised… Tungurahua has been actively erupting since 1999 with major eruptions occurring in 2006 and 2008.

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As with most high volcanoes in the Andes, Tungurahua’s upper slopes are snow-covered and the summit is capped by a small glacier… well, they were until 1999 when the volcano’s eruption quickly melted them away. The greatest danger from such volcanoes is not so much the ash, lava and superheated pyroclastic flows, but flooding and mudslides sweeping into populated areas on the volcano’s lower slopes. The evacuation of 25,000 people from the hot springs resort town of Banos was mainly to safeguard them from that possibility.

Yasur, Vanuatu

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Mount Yasur, on Tanna Island in the South Pacific archipelago of Vanuatu, not only has been erupting for many centuries, but perks up several times per hour! Though just 1,184 feet (361m) in height, Mount Yasur is crowned by an almost perfectly circular summit crater over 1,300 feet (400m) wide.

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Much like Hawaii’s Kilauea, Mount Yasur erupts in a very predictable manner and at a steady level of activity, allowing tourists to approach to very close distances. An example of this was seen during the broadcast of “Survivor: Vanuatu – Islands of Fire”, when players who won a reward challenge enjoyed a picnic of hotdogs and beer while Mount Yasur’s lava fountains provided a unique sound and light show.

Eyjafjallajökull, Iceland

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ast but not least, the noisy newsmaker itself – Eyjafjallajökull. The volcano’s current eruptive phase may have only just begun: its previous eruption which began in December of 1821 lasted well into 1823. Volcanologists have determined that Eyjafjallajökull also erupted in the year 1612, and before that in 920.

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Ominously, each of the three previous eruptions of Eyjafjallajökull were followed by the eruption of Katla, a much larger subglacial volcano just 15 miles (25km) away. In a BBC interview broadcast on April 20, Icelandic President Ólafur Grímsson described the current chaos caused by Eyjafjallajökull as “a small rehearsal”, and warned that “the time for Katla to erupt is coming close… we [Iceland] have prepared… it is high time for European governments and airline authorities all over the world to start planning for the eventual Katla eruption.” C’mon Ólafur, don’t sugarcoat it, give it to us straight, OK?

Just to show that Ólafur isn’t kidding, here’s a video showing what active Icelandic volcanoes like Eyjafjallajökull are all about:

Volcano Eyjafjallajoekull at Iceland, via Marcszeglat

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Some wonder as to the reasons for the increasing appearances of volcanic eruptions in the news media (global warming? The End Times?), but in actuality it’s WE who are appearing more – in closer proximity to active volcanoes than ever before. Population pressure will do that and there’s nothing like an infusion of volcanic ash and minerals to boost the fertility of soil and attract opportunistic farmers. One might say, don’t blame science fiction, instead blame human friction.

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