|
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.
|
