Volcanoes erupt gases, liquids, and solids.
Gases - mostly steam - cause the most excitement.
A quiet flow like this one, a lava fountain, a rain of ash,
a colossal explosion - all depend on how the gas
Liquids - molten lava - may be either fluid or viscous
(sticky). Acid lavas are vicious even at high temperatures;
their trapped gasses often explode violently. Basic
lavas such as these at Craters of the Moon are fluid;
gases escape easily and rarely with explosive force.
Solids come out as blocks of the old cone, bombs,
cinders, ash and dust. Escaping gases whip up molten
lava and explode it out of the vent as solids.