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.

Hundreds of dikes can invade the cone and inner core of a volcano, often along zones of structural weakness. Left: An exposed dike, approximately five feet wide, at the caldera of Mauna Loa ...

"I always marvel that we've been doing human anatomy and gross anatomy for hundreds ... to around three million people living close to the volcano, including metropolitan Naples.” ...