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 ...

Most volcanoes form at the boundaries of Earth's tectonic plates, which are huge slabs of crust and upper mantle that fit together like puzzle pieces. Think of these plates as massive rafts floating ...

At any given time, 20 to 50 of these active volcanoes are erupting. The proximity of people and buildings makes it important to study volcanoes and understand the hazards. The center of the Earth is ...

The 1980 eruption cycle made Mount St. Helens one of the most famous and now best-monitored volcanoes in the Cascades. But it is far from the only volcano in the range. From southern British Columbia ...