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Volcano's Deadly Warning

TV Program Description
Original PBS Broadcast Date: November 12, 2002

 

Volcano's Deadly Warning homepage

In January 1993, six scientists and three hikers were scalded and crushed to death when they ventured into the smoking mouth of the active volcano Galeras in Colombia, confident that no eruption was imminent. This program tells the gripping story of this controversial field trip and the quest to predict when volcanoes will blow.

Tragically, the key to Galeras's impending eruption may have been in plain sight though inadvertently overlooked by trip leader Stanley Williams of Arizona State University. Williams, who suffered two broken legs, a partially severed foot, and a severe brain injury, has subsequently been accused of ignoring the clues and leading his colleagues into a deathtrap from which only a handful escaped.

The warning signs ignored were seismic signals like those recorded during earthquakes. They are the key to a revolutionary new theory that not only could have alerted those on Galeras but may provide accurate advance warning of massive eruptions such as the one that struck Colombia's Nevado del Ruiz in 1985. This eruption sent melting glaciers and mud rushing down onto the city of Armero, where more than 20,000 people perished.

Tremors and smoke have long been omens that a dormant volcano was coming back to life, but no one could say with certainty when or if it would explode. Now, a new theory, developed by Bernard Chouet of the U.S. Geological Survey, focuses on a previously mysterious type of seismic signal. For decades no one knew what the signals meant, but Chouet realized they were signs that magma and gas were surging into a volcano like air being pumped into a tire. Repeated injections of magma and gas create unbearable pressure, and the volcano eventually blows. Chouet's theory was tested in December 2000 to forecast the largest eruption of Mexico's Popocatepetl in a millennium, allowing the orderly evacuation of 30,000 people.

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Colombia's Nevado del Ruiz exploded in 1985, sending mudflows down onto the town of Armero, where more than 23,000 people were killed.




Volcano's Deadly Warning Web Site Content
Volcanoes Talking

Volcanoes
Talking

Bernard Chouet on a seismic signal that foretells eruptions.

Emergency Response Team

Emergency
Response Team

How a crack unit of volcanologists tackles volcanic unrest abroad.

Anatomy of a Volcano

Anatomy of
a Volcano

Distinguish magma from tephra, lava from lahar, etc.

Seismic Signals

Seismic Signals
Discover the hidden volcanic signatures that volcanologists seek.



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