Pyroclastic flows are enormous ejections of debris from erupting volcanoes. They consist of large rocks and smaller particles of ash and dust that travel across the surrounding landscape at tremendous velocity. More » Science Earth Science Volcanoes

Pyroclastic flows travel away from a volcano's vent at speeds up to 150 kilometers per hour. They contain hot gas, ash and rock at temperatures ranging from 100 to 800 degrees Celsius. More » Science Physics Thermodynamics

The danger of pyroclastic flow comes from its speed and heat. According to Michigan Technological University, pyroclastic flows have reached extreme high temperatures, including flows from the Mt. Pelee eruption that got... More »

Composite volcanoes, one of the two main types of volcanoes along with shield volcanoes, are composed of alternating layers of lava and ash or other volcanic debris. These volcanoes are usually cone shaped with steep sid... More »

Active volcanoes can be extremely dangerous to live near because of their tendency to eject debris, gas and harmful chemicals at irregular intervals. According to, any kind of volcano can produce potentially ... More »

The worst thing about living near a volcano is the possibility of it erupting, bringing about many negative consequences, such as earthquakes, lava flows, mud flows, flooding, pyroclastic flows, falling ash, carbon dioxi... More »

Indonesia has the most volcanoes, with 76 volcanoes that have erupted within historical times. The Smithsonian Institution has 141 Indonesian entries in its volcano database; this includes volcanoes which have yet to eru... More »