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RE: Volcanoes
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What are the different types of volcanoes?

Volcanoes are grouped into four types: cinder cones, composite volcanoes, shield volcanoes and lava volcanoes.
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Decade Volcanoes
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The Decade Volcanoes refer to the 16 volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) as being worthy of particular study in light of their history of large, destructive eruptions  and proximity to populated areas. The Decade Volcanoes project encourages studies and public-awareness activities at these volcanoes, with the aim of achieving a better understanding of the volcanoes and the dangers they present, and thus being able to reduce the severity of natural disasters. They are named Decade Volcanoes because the project was initiated as part of the United Nations-sponsored International Decade for Natural Disaster Reduction.
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New insights into volcanic activity on the ocean floor

New research reveals that when two parts of the Earths crust break apart, this does not always cause massive volcanic eruptions. The study, published today in the journal Nature, explains why some parts of the world saw massive volcanic eruptions millions of years ago and others did not.
The Earths crust is broken into plates that are in constant motion over timescales of millions of years. Plates occasionally collide and fuse, or they can break apart to form new ones. When the latter plates break apart, a plume of hot rock can rise from deep within the Earths interior, which can cause massive volcanic activity on the surface.
When the present-day continent of North America broke apart from what is now Europe, 54 million years ago, this caused massive volcanic activity along the rift between the two. Prior to todays study, scientists had thought that such activity always occurred along the rifts that form when continents break apart.

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Volcanic Eruptions in North America Were More Explosive in Ancient Past

Millions of years ago, volcanic eruptions in North America were more explosive and may have significantly affected the environment and the global climate. So scientists report in this week's issue of the journal Nature.
The researchers found the remains--deposited in layers of rocks--of eruptions of volcanoes located on North America's northern high plains that spewed massive amounts of sulphate aerosols into the atmosphere 40 million years ago. The scientists conducted their research at Scotts Bluff National Monument, Neb., and in surrounding areas.

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Man and volcano

In 1783, one such eruption killed about a fifth of Iceland's population, and it sent a huge cloud of toxic ash and sulphurous gases across Western Europe, with the result that in Britain alone, 23,000 people were thought to have died from the poisoning.
Less than one hundred years later, in 1873, another monster Icelandic eruption sent clouds and ashes across much of Scandinavia. So this latest volcanic intrusion into our lives is but the most recent in a long and ominous historical sequence, and there is no reason to suppose that it will be the last: indeed, the Icelandic prime minister has already said as much.
By the time of the terrible Icelandic eruption of 1783, excavations had been proceeding for several decades in Italy to uncover what remained of the Roman town of Pompeii, and its near neighbour Herculaneum, both of which had been overwhelmed by the lava from Mount Vesuvius.

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The volcano in Iceland may have caused some chaos and misery, but the fact is we got off lightly. One day there will be an eruption that could wipe out the human race
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Glaciovolcanoes
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Scientists Study "Glaciovolcanoes," Mountains of Fire and Ice, in Iceland, British Columbia, U.S.

Glaciovolcanoes, they're called, these rumbling mountains where the orange-red fire of magma meets the frozen blue of glaciers.
Iceland's Eyjafjallajökull volcano, which erupted recently, is but one of these volcanoes. Others, such as Katla, Hekla and Askja in Iceland; Edziza in British Columbia, Canada; and Mount Rainier and Mount Redoubt in the U.S., are also glaciovolcanoes: volcanoes covered by ice.

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The eruption of the Icelandic volcano that has caused so much disruption in the UK and Europe is really nothing unusual.
For hundreds of thousands of years, periodic eruption of Icelandic volcanoes has produced ash that has been carried over the British Isles.
This ash settles down into peat bogs and lakes, where it forms consistent layers. Nowadays, geologists and geographers find the ash incredibly useful, because each ash layer can be analysed and linked to a known eruption, allowing us to work out the age of the surrounding peat or lake sediments.

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It seems that the volcanic ash - even now creeping over the UK like a slightly low-rent piece of CGI in an under-scripted horror movie - could also affect satellite communications. John Yates, Chair of the Institution of Engineering and Technology (IET) Satellite Network, says: "The 1991 Mount Hudson volcano eruption - one of largest of the 20th century - affected satellite communications systems in Chile. The ash affected satellite communications in Los Antiguos, a town 120km from the volcano, in the same manner as a snow storm can disrupt satellite communications."
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Flights have been disrupted across northern Europe by volcanic ash drifting south and east from Iceland.
Airspace was closed or flights cancelled in countries including the UK, the Republic of Ireland, Denmark, Norway, Sweden and Finland.
The ash, which can damage aeroplane engines, was produced by a volcanic eruption under a glacier in Iceland.

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