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Is the world ready for Yellowstone?
Tue, 04 May 2010 15:14:40 GMT
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by Tahereh Ghanaati

Air traffic throughout Europe was brought to a screeching halt and commerce was seriously impeded by the recent eruption of Iceland's Eyjafjallajokull volcano. Moreover, the mayhem was not limited to the European continent. The entire world was affected as airlines from Thailand to Texas and from Australia to Abu Dhabi wrestled with a backlog of stranded passengers.

Our planet has often been described as a global village, but the truth of the description had not really been driven home until a mountain on a remote Atlantic island nation erupted and poured volcanic ash into the atmosphere, causing the intricate machinery of modern civilization to seize. People around the world were affected; from the Kenyan asparagus farmer, who had to end up feeding his cows delicacies originally meant for European gourmands, to the American bride, who had to forego the spring bouquet of Dutch tulips she had ordered for her wedding, to the Belgian diamond cutter, who was unable to receive a shipment of rough diamonds from India.

People across the financial spectrum were affected in virtually every part of the world -- and that is just a small part of the picture. As the media has already pointed out, ordinary businesspersons, as well as heads-of-state, were stranded either at home or abroad and forced to miss meetings and international events. Trips of a lifetime were derailed. Long-anticipated graduation parties, family reunions and weddings were missed. The Iceland event showed even the most confident among us how fragile and dependent upon the caprices of nature our society still is.

The truly disquieting aspect of the incident, however, is the fact that Eyjafjallajokull is not really that big a volcano - not compared to nearby Mount Katla, its much larger sibling, which, in turn pales in significance to the world's true volcanic giants - the so-called 'super volcanoes' that fitfully slumber beneath the Earth's surface.

Unlike your usual, run-of-the-mill volcanoes, which are known for their distinctive cone shape, a super volcano's caldera (depression in the Earth equivalent to a crater) is so large it can only be identified from the air. To date, seven active or dormant (potentially active) super volcanoes have been identified throughout the world. They include: the Siberian Traps, the Aira caldera, the Taupo volcano, Lake Tobia, the Valles Caldera, the Long Valley volcano and the Yellowstone volcano. The Siberian Traps, as the name implies, is located in Siberia, Russia. Aira is in Japan, Taupo is in New Zealand and Lake Tobia is located in Sumatra, Indonesia. The last three (the Valles Caldera, Long Valley and Yellowstone), are all located in the western portion of the United States -- in New Mexico, California and Wyoming, respectively. Of all of these, Yellowstone, with its active ground deformation (rising lava dome), 10,000 thermal elements and numerous earthquakes (approximately 1,000 to 3,000 a year), is the most active. It is also one of the largest.

The term, 'super volcano', initially coined by the media, has become fairly common in recent years, but a number of people are still uncertain as to its exact meaning. What makes a volcano 'super'? What characteristics does such a volcano possess that make it different from 'regular' volcanoes and, more importantly, what would happen if a super volcano were to explode?

To answer those questions, let's take a closer look at Yellowstone (the most active and thereby, the most potentially dangerous of the aforementioned giants) and compare it with other 'regular' volcanoes. The first thing we notice is that a super volcano is much bigger. For example, the crater at the top of Mount St Helens in the state of Washington measures 1.9 by 2.8 kilometers and the crater on Iceland's Eyjafjallajokull measures approximately 3 to 4 kilometers in diameter, whereas the measurements of Yellowstone's caldera register at 35 by 72 kilometers.

Then, there is the power of the eruption to consider. When Mount St. Helens blew in 1980, it hurled 1.4 billion cubic yards of ash into the air, which was detectable for over 22,000 square miles (35,405.568 sq. km) in 11 different states. Fifty-seven people were killed. The biggest eruption in the past two hundred years was that of Mount Tambora in 1815 in Sumbawa, Indonesia. The blast shot 160 cubic kilometers of ash into the atmosphere, causing a worldwide drop in temperatures and triggering a change in climate, known as a "nuclear winter." At least 71,000 people lost their lives.

In contrast, Yellowstone's last eruption (around 640,000 years ago), expelled approximately 1,000 cubic kilometers of ash and volcanic debris into the air, covering the western and mid-western sectors of the United States as well as Mexico. The blast was 3,000 times stronger than the historic eruption of Mount Vesuvius in 79 C.E. and 1,000 times more powerful than the 1980 Mount St. Helens blast.

Experts agree that the consequences of another similar event (a caldera-forming eruption, such as those, which occurred at Yellowstone 2.1 million, 1.3 million, and 640,000 years ago, respectively) would be devastating. If the Eyjafjallajokull eruption threw the world system off-kilter, we can only imagine what would happen if Yellowstone were to blow. Firstly, the initial blast would kill nearly every living thing within a 600-mile (965 km) radius. The entire North American continent would be devastated and the ash cloud would be swept much further, blocking out sunlight, causing global temperatures to plummet and plunging the Earth into a long-term nuclear winter; but that is only the beginning.

Air traffic throughout the world would be halted for an extended period of time; thus commerce and trade - as we know them today - would cease to exist. Stock markets would crash, causing an economic domino effect. The eruption would devastate the US Great Plains bread basket causing widespread food shortages. The ensuing cold temperatures and lack of sunlight --experts can only surmise as to how long these conditions might last -- would further aggravate the problem, preventing harvests elsewhere and causing famine throughout much of the world.

The only other incident in human history of similar catastrophic proportions occurred 73,000 years ago when the Toba super volcano blew in Sumatra. Like the Yellowstone blast 640,000 years ago, the Toba eruption was 1,000 times more powerful than the Mount Saint Helens event.

Some experts maintain that the nuclear winter resulting from the Toba eruption lasted from 6 to 10 years. In fact, according to one theory, initially explored in 1993 by Michael R. Rampino of New York University and Stephen Self of the University of Hawaii at Manoa, fossil evidence indicates a link between the eruption, its effects and the bottleneck in human evolution. The theory, which was later developed (in 1998) by Stanley H. Ambrose of the University of Illinois at Urbana-Champaign, holds that the nuclear winter caused by the Toba event resulted in a drastic reduction in the human population. According to some proponents of this theory, only 3,000 to 10,000 persons survived. If that theory is correct, the Toba blast posed a major threat to continued human survival.

Is a similar scenario likely to occur at Yellowstone? Despite the United States Geological Survey organization's (USGS) assurances to the contrary, mounting evidence paints a disquieting picture. As has previously been mentioned, the lava dome on the floor of the crater has risen significantly since measurements were begun in 1923 and earthquakes appear to be increasing in frequency. In January and February of 2010, an intense swarm of ~2,350 earthquakes occurred. The temblors then began to taper off in number and intensity until late March and early April, when more than 30 took place in the same area as the earlier swarm. The rate of occurrence of the latter group was not really unusual for Yellowstone, in which more than 80 separate swarms of earthquakes have been identified as taking place within the past quarter century.

Most volcanologists maintain that if Yellowstone were to blow, the most likely eruption to occur would be hydrothermal rather than volcanic - a small explosion that would eject superheated steam rather than volcanic ash and lava. They also believe that if a volcanic eruption were to occur, it would most likely produce a lava flow of rhyolite or basalt. This type of eruption could range in size from something smaller than the 1980 Mount Saint Helens incident to something much larger than the 1991 Mount Pinatubo event. However, these experts do admit that a full-fledged eruption, such as the one that occurred at Yellowstone 640,000 years ago, cannot be ruled out. As well as can be ascertained, a major eruption occurs every 600,000 to 700,000 years so we have either entered -- or are approaching -- the time frame.

There are still many questions surrounding Yellowstone and experts differ on a number of areas; but there are two major points on which they concur. They are that one day another major eruption will take place at Yellowstone - it is not a matter of possibility, but of time. And when that does occur, the results for humankind will be cataclysmic. Until that day, all we can do is monitor the smoldering rumblings of this subterranean giantess, who appears to be awakening from her age-old slumber.
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