1001 Space Earth Earth Rocks and Minerals Landscape Sea Weather and Climate Natural Disasters Resources Nature History Human World Science and Technology

Choose a Page:Where are extinct volcanoes found?What makes an avalanche so deadly?*What happens inside a volcano?*What causes landslides?What causes an earthquake?Are some volcanoes more dangerous ...What is a caldera?How does wildfire spread?What is a waterspout?Can disasters be predicted?Where do volcanoes happen most?Is a typhoon the same thing as a h...Is a twister like a hurricane? What happens inside a volcano? Volcanoes generally have a central vent surrounded by a steep-sided cone formed from layers of lava and ash. As the magma rises from beneath the Earth's crust, it may become contaminated by local rocks that change its chemical composition, making the eruptions more violent. Ejected debris may range from ash to huge volcanic bombs that weigh several tons. A section through a volcano shows how the cone is built up from solidified lava, ash, and rock debris deposited by successive eruptions.   Previous: Back Book: 1001 Section: Earth Chapter: Natural Disasters