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Transcript
July 14, 2003
Narrator: A volcano erupts. It's a force of nature that can devastate lives.
C. Dan Miller (US Geological Survey): Volcanoes are very attractive places to live. Volcanic eruptions produce very rich soils and in many countries in the world, some of our most productive cropland is on the flanks of volcanoes.
Narrator: As shown on PBS's NOVA, a volcano erupts when hot gas and magma, molten rock that flows into a volcano through the earth's crust, rise to the surface. If the volcano's top is sealed, they have nowhere to go. Pressure builds and the volcano blows. Every volcano is different, so eruptions are hard to predict. But some volcanoes do give off telltale warnings and today there is technology in place to detect them. Seismographs report pre-eruption earthquakes, gas detection devices pick up emissions, and satellites and radar track changes in shape and ground elevation. With these tools, scientists are better equipped to help determine when it's time to evacuate an area.
Bernard Chouet (US Geological Survey): The ultimate quest is to understand enough about the activity in that volcano to be in a position to make a prediction, predict the occurrence of an eruption.
Narrator: And to keep a natural process from becoming a natural disaster. I'm Brad Kloza.
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