Wednesday, June 25, 2008

When volcano gets angry

A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot, molten rock, ash, and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time.

Volcanoes are generally found where tectonic plates are pulled apart or come together. 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 usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intraplate volcanism"), such as in the African Rift Valley, the Wells Gray-Clearwater Volcanic Field and the Rio Grande Rift in North America and the European Rhine Graben with its Eifel volcanoes.

Volcanoes can be caused by "mantle plumes". These so-called "hotspots" , for example at Hawaii, can occur far from plate boundaries. Hotspot volcanoes are also found elsewhere in the solar system, especially on rocky planets and moons.

credited to wikipedia and flickr users: volcanodiscovery, photovolcanica, dmustaine, guano, sandy-leemans, ibhmc, hageonline, contactgmt, franck

4 comments:

Chanelle said...

OMG! Why did they build a house so close to the volcano? Hope the mortgage was dead cheap, lol.

Lots in Costa Rica said...

I recently came across your blog and have been reading along. I think I will leave my first comment. I don’t know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often.

Viagra Online said...

amazing pictures! I was once in the Krakatau volcano, in Indonesia and the eruption was scarily big but at the same time beautiful and it amazed me the power of nature!

Generic Viagra Viagra

generic cialis said...

Thanks for the nice blog. It was very useful for me. Keep sharing such ideas in the future as well. This was actually what I was looking for, and I am glad to came here! Thanks for sharing the such information with us.