<P> Lava is molten rock generated by geothermal energy and expelled through fractures in planetary crust or in an eruption, usually at temperatures from 700 to 1,200 ° C (1,292 to 2,192 ° F). The resulting structures after solidification and cooling are also sometimes described as lava . The molten rock is formed in the interior of some planets, including Earth, and some of their satellites, though such material located below the crust is referred to by other terms . </P> <P> A lava flow is a moving outpouring of lava created during a non-explosive effusive eruption . When it has stopped moving, lava solidifies to form igneous rock . The term lava flow is commonly shortened to lava . Although lava can be up to 100,000 times more viscous than water, lava can flow great distances before cooling and solidifying because of its thixotropic and shear thinning properties . </P>

Where does the lava that erupts from volcanoes come from