Volcano

[Randy]

A volcano is an opening, or rupture, in the surface or crust of the Earth or a planetary mass object, which allows hot lava, volcanic ash and gases to escape from the magma chamber below the surface.
On Earth, volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are not usually created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust in the interiors of plates, e.g., in the East African Rift, the Wells Gray-Clearwater volcanic field and the Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "Plate hypothesis" volcanism. Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth.
Erupting volcanoes can pose many hazards, not only in the immediate vicinity of the eruption. Volcanic ash can be a threat to aircraft, in particular those with jet engines where ash particles can be melted by the high operating temperature; the melted particles then adhere to the turbine blades and alter their shape, disrupting the operation of the turbine. Large eruptions can affect temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere. Historically, so-called volcanic winters have caused catastrophic famines.

Have you ever seen one in real life? Would you like to?

Did you ever do a volcano project in school?

 

[DrLeftover]

Yes, to all of the above.

Someplace around here there are pictures of me at Kīlauea before it started the current eruption cycle in the Seventies.

But I find the "super" variety of the critter even more fascinating.

And when you find out how many of them there are, and what happens to the Earth when one cooks off, they are also terrifying.

In the category of Supervolcanos you have Yellowstone, Toba in Indonesia, the Campi Flegrei in Italy, maybe even the earlier Krakatoa explosion in about 500 AD but maybe not the one in the 1880's. These things cook off every so often and spew enough ash and gas into the atmosphere to cause a planet wide ice age.
...
Where are the Super Volcanoes:
What surprises most people is how many of these things there are, and how big some of them actually were/ are.
Anywhere from about 250,000 years up to maybe half a billion years ago (depending on which research paper you read) a massive eruption covered most of Siberia in what is now Russia with lava. Something similar happened some time later in India and created the Deccan Traps which cover several thousand square miles with lava up to two thousand feet thick.
Another ancient eruption covered a good section of India and became silent. The Long Valley in California is an active area whereas the La Garita Caldera in Colorado seems to have erupted only once.
Others, such as Krakatoa, are more famous for other reasons than being a large, long dead crater.
Many of these types of volcanoes are part of the Pacific Ring of Fire. You could think of Yellowstone and Sumatra as part of its extended reach. New Zealand's Taupo most certainly is, and it has been showing signs of life, just like its cousins, Krakatoa and Yellowstone.
Given that the Rift Valley in Africa is too ancient to accurately diagnose, giant explosive volcanoes have been identified on every continent except South America and possibly Antarctica.

....
The very active Aso/ Aira volcanic complex (actual supervolcanoes mixed in with regular volcano volcanoes) in Japan once produced a pyroclastic flow that covered almost half the island of Kyushu, which is now home to well over a million and a half people.

http://themediadesk.com/files9/disasters.htm

 

[Krihol]

I have never seen one. I don't really want to see one neither.. But i think we had a small project about it when i was a little kid.. Don't really remember it tho.

 

[Bjornar]

I have never seen one either. I want to though, and i would love to see some lava.

 

[DrLeftover]

And Kilauea is still active.....

Pāhoehoe lava on the Kahaualeʻa 2 flow invades the forest northeast of Puʻu ʻŌʻō, burning and toppling trees and creating plumes of smoke.

Just in case you are interested in learning more:




HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE

With link to current status and active webcams-

http://hvo.wr.usgs.gov/activity/kilaueastatus.php

 

[Nebulous's iconNebulous]

And Kilauea is still active.....

Pāhoehoe lava on the Kahaualeʻa 2 flow invades the forest northeast of Puʻu ʻŌʻō, burning and toppling trees and creating plumes of smoke.

Just in case you are interested in learning more:




HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE

With link to current status and active webcams-

http://hvo.wr.usgs.gov/activity/kilaueastatus.php

Thanks for sharing that pic! I am surprised some of those tree's are still standing.

 

[Tyler]

I wouldn't mind seeing one but I'd be distant from it.

 

[Krihol]

Lets everyone go and see one! And then we throw Bjornar in the lava.

 

[DrLeftover]

Etna

26 Oct

An eruption by Europe's most active volcano has sent a tower of sparks and fire into the sky around it.

The plume of ash rising from Mount Etna can be seen across much of eastern Sicily. Its eruptions are not infrequent, but the last major one occurred in 1992.

With video:

http://www.bbc.co.uk/news/world-europe-24688230