What Causes Volcanoes?

Volcanoes explode because of the gas buildup. When the gas builds up a lot, the gas and lava, which is hot rocks, blows out the top, it’s a lot like the way a soda explodes. The lava can get up to 1600 degrees - a lot hotter than an oven. After the lava cools, it turns into rock. One of the types of rock is obsidian, which is shiny and black. Volcanoes can also occur on other planets and in the ocean. Not all volcanoes explode, some are inactive and some are dormant (asleep).

The lava can kill people, but there can be other problems. If there’s heavy rains on the ash it creates a thick mud that has trapped people and animals. When all the trees and plants are destroyed by the lava, the animals have nothing to eat.

Lots of volcanoes happen in the “Ring of Fire” which is from California to Asia. There are large tectonic plates in the Ring of Fire and lots of earthquakes happen here too.

sources:

http://www.nsf.gov/nstw_questions/eart/quest083.htm
http://www.geosc.psu.edu/~jrogie/ans11-3.html
http://www.volcanoworld.org/
http://pubs.usgs.gov/publications/msh/contents.html
http://pubs.usgs.gov/publications/msh/continuing.html
http://www.volcanoes.com/
http://www.geology.sdsu.edu/how_volcanoes_work/Home.html