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 remember Pinatubo. We rarely got 80 Degree days that summer and we usually hit the upper 80's.
Yup, That was 1816, The Year Without Summer.
"I remember Pinatubo. We rarely got 80 Degree days that summer and we usually hit the upper 80's."
The plume from Pinatubo was 26 miles high. The plume from Thera would have had to be 30 miles high for it to have been seen in Egypt. (Exodus, "Staff By Day, Torch By Night")
Don't know, nothing in my headlights. The volcanos Nyiragongo (Congo) and Gamalama (Indonesia) lighted up in 1884 but, they go off often.
Thanks for the vote of confidence, you get it!
I'm curious if you have any links to definitive evidence on this. There seems to be disagreement on this in a couple books that I've just read (both books from about 2000). David Keys, in his book Catastrophe, thinks that a volcano (proto-Krakatoa as he calls it) caused the Dark-Ages event. He cites acid in ice core samples from Greenland (2 different ones) and Antartica (pages 245-8). He even has a chart, so he must be right, ;). Mike Baillie thinks that a comet caused the 540 event and writes in the update to preface of his book, Exodus to Arthur, that "it can still be stated that there is no good evidence for an exceptional volcanic event in the immediate vicinity of AD 540...".(citing ice core evidence, p.8)
I know that you're probably very familiar with both theories and their evidence; maybe you can point me in the right direction. Also, if the dark-ages event was caused by a comet, couldn't that also trigger volcanic activity of some sort? It seems to me that you would expect to see acid evidence in core samples with a comet impact because of this.
On another topic: it sounds to me like some people believe that if one of these "global" events were to occur today, that all we would have to worry about is the eruption or impact and its immediate effects. From what I've read, it looks like we may be affected for up to 30 years (and maybe longer) depending on the magnitude. With the population of the world being what it is today, even a relatively "minor" global event could possibly cause a shift in global political power (depending on where this event occurs of course). It looks like just a couple degree change in global temps could set off a domino effect of floods, drought, food shortage, plague, mass migrations, war, etc. At least this seems to be the lesson of history- or does our technology put us above all that today? LOL (maye I should stop reading these books)
You're welcome. If you run out, go to the links on my profile page and to * Gods, Graves, Glyphs, see the link in post #39 by 'farmfriend'.
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