Song of the Earth

Something truly remarkable has happened and yet hardly anyone knows about it. If it were not for the PBS program called NOVA:Volcano's Deadly Warning I would not know about it. I am talking about our (humankind's) ability to predict volcanic eruptions.

Enter one Bernard Chouet (pronounced: Shooway) of the US Geological Survey and his new interpretation of seismic readings - we now have a way of predicting an eruption to within days if not hours. In a dramatic fashion this method was used to warn and evacuate unsuspecting people within hours of devastating eruptions.

Using existing seismic readings but focusing on previously discarded seismic events known as type B events Chouet was able to interpret their meaning and use them as reliable predictors of eruptions. These events, he has since renamed 'long period events' had baffled scientists for years. He explained that what they are is resonance. Like the sound of air resonating in the long hollow tube of a pipe organ. This is the volcano literally singing its song to us. The song of the Earth.

Chouet's theory: the more of these long period events the closer an eruption is.

Using this untried method of prediction Chouet and authorities in Alaska used every ounce of their persuation to get an oil storage facility at the base of Mt Readoubt to shutdown the operation and evacuate. This, of course, was not a suggestion taken lightly as they were millions of dollars at stake in shutting down such a facility. At 4pm that day the last man drove out of the compound and within an hour the volcano erupted. Because the oil storage had been properly sealed none was lost, but more importantly no human casualties occured. Had they not shutdown and evacuated it would have been a tragedy.

In Columbia the volcano Galeras became the site of a challenge of theories; Chouet's long period event method versus Stanley Williams' volcanic gas method. Williams believed that as a volcano was pending an eruption that it would emit more and different gasses than a during a more stable period. The first round was a draw as both men were able correctly predict an eruption.

Months later Williams returned to Galeras - this time with a group a volcanologists. The highlight of the conference was a trip to the lava dome in the center of Galeras. Williams, having done his gas readings the previous day, had declared the mountain safe. However, the seismic readings were "singing" a different tune. Chouet was not in attendance but his lessons were not lost on Columbian scientists who put out a cautionary warning about going to the crater that day. In the end nine people died when Galeras erupted just as Chouet's theory predicted.

In Mexico some years later Chouet warned the authorities that the volcano Popocatépetl was about to erupt. The dilemma for the Mexican authorities was when to ask people to evacuate. If it was too soon and nothing happened then people would surely resist ever leaving again. If it was too late, well, it was too late and people would die.

When the decision was made two thousand soldiers were dispatched to move 30,000 people from their homes. Just as the last of them got out of town the volcano erupted - just as predicted.

It is a remarkable thing Chouet has done, but what I found most intiguing was his descritption of the long period event as the volcano singing a song. Could it be that the Earth is literally alive? Now imagine the thousands of volcanos on the Earth singing in some kind of epochical choir that spans the centuries. For all we know these sounds travel through space and time to communicate with other heavenly bodies. Could the Earth be just a giant bagpipe in a cosmic orchestra? Intriguing, isn't it?

What Chouet has really taught us is that the answers to some of our deepest questions are already there - we just have to learn how to interpret them.

CW