Whenever there is a major volcanic eruption in the world, you'll see a slew of newspaper articles and nightly news stories covering the catastrophe, all stressing a familiar set of words -- violent, raging, awesome. When faced with a spewing volcano, people today share many of the same feelings volcano-observers have had throughout human history: We are in awe of the destructive power of nature, and we are unsettled by the thought that a peaceful mountain can suddenly become an unstoppable destructive force!
Lava is molten rock expelled by a volcano during eruption. When first expelled from a volcanic vent, it is a liquid at temperatures from 700 °C to 1,200 °C (1,300 °F to 2,200 °F). Although lava is quite viscous, with about 100,000 times the viscosity of water, it can flow great distances before cooling and solidifying, because of both its thixotropic and shear thinning properties.