A wall of lava flows down Hoʻokāpu Street on Hawaii's Big Island, engulfing cars and setting trees ablaze – one of many scenes of havoc following the eruption of Kilauea in May.
Deriving their name from the Roman god of fire, Vulcan, volcanoes live up to their reputation as one of nature's most fearsome phenomena. Literally openings in the earth's surface, volcanoes exist throughout the world, including underwater.
Volcanoes usually occur where tectonic plates separate but they can also arise from hot spots in the earth's crust, such as in the Hawaiian Islands and Yellowstone National Park. When pressure builds up and travels to the earth's surface, an eruption occurs that can last between one hour and hundreds of years. The Island of Stromboli's volcano has been continuously active for over 2,000 years.
In addition to lava, ash and fire, eruptions are often accompanied by earthquakes, mudslides, and acid rain, causing massive damage to the surrounding environment. The 1980 eruption of Mount St. Helens destroyed 200 houses, 15 miles of highway and 4 billion board feet of timber.
Volcanic eruptions are not solely destructive, however. The lava they produce can clear away brush and treat the soil, making the land highly fertile for new plants and agriculture.