Posted on 08/29/2003 5:37:16 PM PDT by blam
Signs of an eruption
For days before the eruption the volcano had been screaming 'I'm about to explode'
Bernard Chouet
A scientist has found a way to use earthquakes to predict when volcanoes will erupt. Swiss scientist Bernard Chouet fell in love with volcanoes when he witnessed spectacular fountains of lava spewing from Sicily's Mount Etna in 1969.
Now at the US Geological Survey, Chouet has devoted his career to finding a way to predict deadly volcanic eruptions. He is haunted by a disaster in South America that killed 25,000 people.
When Colombia's Nevado del Ruiz volcano erupted in 1985, it melted a glacier capping the mountain. Water and volcanic ash combined to produce devastating mudflows that wiped the entire town of Armero off the map.
By then Chouet had developed a theory that volcanic eruptions should be preceded by a type of earthquake he called a long period event.
Chouet believed that long period events were a sign that pressure was building up inside a volcano.
When he finally saw the earthquake records from Nevado del Ruiz, a year on from the disaster, he was horrified.
Tragic misjudgement
Chouet saw long-period events all over charts. For days before the eruption the volcano had been screaming "I'm about to explode" but no one had heard the warning.
Vesuvius volcano
In the early 1990s another Colombian volcano, Galeras, became restless. Long period events had again appeared on the charts - a clear sign of an impending eruption, according to Chouet.
But US volcanologist Stanley Williams was sceptical about Chouet's approach. Apart from the long period events the volcano was completely quiet.
So on 14th January 1993 Williams led a group of scientists into the crater of Galeras to measure gas emissions.
It was a tragic misjudgement. As they were preparing to leave the crater the volcano erupted, killing six of his colleagues and three tourists. Williams himself was severely injured.
In December 2000 Chouet was vindicated in dramatic fashion. For several years the mighty Popocatépetl on the outskirts of Mexico City had been gently steaming.
Fumarole volcano But then the long period events started - so many that they merged into a continuous tremor that could be felt in nearby villages.
Using Chouet's methods scientists at the National Centre for Prevention of Disasters in Mexico City predicted that there would be a large eruption in two days. The government evacuated tens of thousands of people.
Forty eight hours later, bang on time, the volcano erupted spectacularly. It was Popocatépetl's largest eruption for a thousand years and yet no one was hurt.
I expect so.
How could they know?
I mean, it was dark and all
Thanks, I saw that.
I wonder if this is one of Chouet's long period events?
Nah, Yellowstone is 28x47 miles
Now you did it! I hope it blows tomorrow now just to prove you wrong!
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(kidding...:^)...)
Actually, I believe in the case of these cauldera volcanos that the magma pools in a large reservior under the surface under high pressure. The high pressure keeps trhe gases trapped in the magma from expanding. A sudden release of pressure would cause all the gas trapped in the magma to expand at once causing an explosion rather than an eruption. They say the sound would be heard around the world. When they say "explosion", I assume they mean a time period of minutes or hours instead of a couple days would be all it would take to release several hundred cubic miles of magma.
Hey, I don't make this stuff up. The truth is astonishing enough, huh?
"From: U. S. National Park Service Website, Geology Fieldnotes - Yellowstone National Park, April 2000
At the heart of Yellowstone's past, present, and future lies volcanism. Catastrophic eruptions occurred here about 2 million years ago, then 1.2 million years ago, and then 600,000 years a go. The latest eruption spewed out nearly 240 cubic miles of debris. What is now the park's central portion then collapsed, forming a 28- by 47- mile caldera (or basin). The magmatic heat powering those eruptions still powers the park's famous geysers, hot springs, fumaroles, and mud pots. The spectacular Grand Canyon of the Yellowstone River provides a glimpse of Earth's interior: its waterfalls highlight the boundaries of lava flows and thermal areas. Rugged mountains flank the park's volcanic plateau, rewarding both eye and spirit.
I believe this one (linked below) may have been the end of 'Soddom and Gomorrah' and provided the imagery for Revelations. This crater wasn't discovered until Saddam drained the homeland of the 'Swamp Arabs.'
Just five minutes ago the Weather Channel gave a 'Asteroids and you: It don't look good' segment.
Catastrophism IS fun, but are they trying to tell us something?
Probably. The angel Gabriel reportedly gave the rock to Abraham...many view 'angels' as being meteorites. Gabriel may have been a meteorite?
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