Volcanoes are grouped into four types: cinder cones, composite volcanoes, shield volcanoes and lava volcanoes. Cinder cones are circular or oval cones made up of small fragments of lava from a single ...

Deadliest volcanic eruption: The 1815 eruption of Mount Tambora in Indonesia, which killed up to 100,000 people From lava fountains to towering ash clouds, volcanoes produce some of the most dramatic ...

(CNN) — Here's some background information about volcanoes, mountains that open downward to a reservoir of molten rock. Facts: More than 80% of the Earth's surface, both above and below sea level, is ...