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 ...

Though its last eruption was a century ago, California's Lassen Peak is the centerpiece of a volcanic panorama.

(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 ...

Above Wenatchee, spires reveal volcanic history in 44-million-year-old rock. High above the city of Wenatchee, Washington, a group of spires made of a unique type of 44-million-year-old rock tell the ...

A volcano is an opening in the Earth's crust that allows molten rock, gases, and debris to escape from below the surface. The molten rock that rises in volcanic vents is known as 'magma', and after it ...