The volcanoes featured in the NOVA program "Volcano's Deadly Warning"—Galeras, Nevado del Ruiz, Popocatepetl, and Mt. Redoubt—as well as many other famous volcanoes, including Mt. St. Helens ...

Lava is the word for magma when it erupts onto the Earth's surface. Geologists also use the term to describe the solidified deposits of lava flows and fragments hurled into the air by explosive ...