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.
Calderas are entirely different from individual volcanes. We've never witnessed an entire large Caldera erupting (though we've seen large eruptions of individual volcanoes at large calderas like Rabaul).
It seems exceedingly unlikely you'd see a large caldera blast without quite a bit of obvious warning signs over a long period of time.
Okay, if you say so.
"What would be the effect of an eruption?
Immediately before the eruption, there would be large earthquakes in the Yellowstone region. The ground would swell further with most of Yellowstone being uplifted. One earthquake would finally break the layer of rock that holds the magma in - and all the pressure the Earth can build up in 640,000 years would be unleashed in a cataclysmic event. Magma would be flung 50 kilometres into the atmosphere. Within a thousand kilometres virtually all life would be killed by falling ash, lava flows and the sheer explosive force of the eruption. Volcanic ash would coat places as far away as Iowa and the Gulf of Mexico. One thousand cubic kilometres of lava would pour out of the volcano, enough to coat the whole of the USA with a layer 5 inches thick. The explosion would have a force 2,500 times that of Mount St. Helens. It would be the loudest noise heard by man for 75,000 years, the time of the last super volcano eruption. Within minutes of the eruption tens of thousands would be dead.
The long-term effects would be even more devastating. The thousands of cubic kilometres of ash that would shoot into the atmosphere could block out light from the sun, making global temperatures plummet. This is called a nuclear winter. As during the Sumatra eruption a large percentage of the world's plant life would be killed by the ash and drop in temperature. Also, virtually the entire of the grain harvest of the Great Plains would disappear in hours, as it would be coated in ash. Similar effects around the world would cause massive food shortages. If the temperatures plummet by the 21 degrees they did after the Sumatra eruption the Yellowstone super volcano eruption could truly be an extinction level event.
Yes, if you are within a 1000 miles of this blast then you are screwed, but if you are outside that range, you'll probably be fine.
But the humanity and the world are a lot tougher than you think.
Also, note that the last Yellowstone blast was much smaller than the one before that. If we are lucky this next blast will be the smallest one yet, probably equal to the Island Park blast.
Bad, but not the end of the world.
Yes, if you are within a 1000 miles of this blast then you are screwed, but if you are outside that range, you'll probably be fine.
But the humanity and the world are a lot tougher than you think.
Also, note that the last Yellowstone blast was much smaller than the one before that. If we are lucky this next blast will be the smallest one yet, probably equal to the Tambora blast.
Bad, but not the end of the world.
Soylent green?
Without a doubt, I'm a catastrophist.
Tree rings worldwide have recorded five catastrophic events (some call them 'near-extinction' events) in the last ten thousand years, They are: 3195BC, 2353BC, 1628BC, 1159BC and 540AD. All these events, except for 540AD event, are recorded in the ice cores as acid layers which is the signature of volcanos. The 540AD event is believed to have been caused by a meteorite or comet fragments (no acid layer) plunging into the Celtic Sea and was the event that brought on the Dark Ages. (BTW, the Dark Ages was a worldwide event, not just Europe).
I'm not an eco-nut and don't think you take the potential serious enough.
I'm not alarmed either.
My main interests are archaeology/anthropology and I use these catastrophic events to trace the movement and history of humans across the world. Click on the links on my profile page and you'll see the 'trend' from the articles I have bookmarked there.
For example, I've often wondered how many humans were killed during the impact that caused the Barringer Crater in Arizona 50k years ago. (Yes, I believe there were humans here then)
Yup, love it. The tree ring chronology is now over 10k years. Some of the dendrochronologists are so good, they can read these rings with out any reference book, etc.
I figure the folks near the poles have the best chance with the worst case scenerio. They are already prepared for cold and any humans and animals that starved to death would freeze and provide food for the future when unfrozen.
Yup, I read that too. Interesting stuff.
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