Super Volcano threat to North America.



Eruption danger?

The Yellowstone volcano in the USA may one day wipe out North America and threaten life on the planet. But how likely is this scenario?

     

Super Volcano threat to North America.

Major catastrophe.

Some experts believe that a super volcano in the United States may soon erupt with such force as to lay waste much of North America. Moreover they believe that such an event may now be imminent and would constitute a major catastrophe whose effects would be felt around the world and push Mankind to the very brink of extinction.

Yellowstone Volcano.

The volcano in question is the Yellowstone Super Volcano in the United States of America. This is a relatively young volcano but its immense size and the power of its previous eruptions – amongst the largest in recorded world history – mean it poses a threat of considerable proportions.

Unbelievable power.

Some indication of the enormity of the power involved in these eruptions, thousands of times more powerful than a normal volcano can be judged from the first astonishing eruption of the Yellowstone around 2.1 million years ago. This was so potent that it gouged out a crater 85 kilometres long by 60 kilometres wide – a truly phenomenal eruption that had it happened today would have come close to obliterating the whole of the United States. That isn’t to mention the broader implications for the world as a whole, with volcanic ash obscuring the Sun and likely to have enormous consequences on world weather, agriculture, and quality of life.

Altered world.

So one thing is for certain – if there were another volcanic eruption of these dimensions it would fundamentally alter the world as we know it. But is such an eruption imminent? If so when is it likely to occur? To answer this let us look at what we know.

Astonishing periodicity.

The Yellowstone Volcano is relatively young, in fact surprisingly young. Moreover during the course of its two million years of life it has erupted with astonishing periodicity around once every 600,000 years. Some experts feel that another eruption is well overdue. But how justified is this claim?

Rising caldera

The fact is that until recently the Yellowstone has not attracted much concern. In the 1970’s however scientists noticed  there had been a two feet rise in the vertical level of the Caldera and this prompted closer investigation of the Yellowstone which is now monitored around the clock. From this study we know that the caldera rises and falls over time and is now said to be bulging towards the Southwest. In addition the north side is estimated to have bulged around 170 feet in the last 50 years. But are these bulges indicative of a coming eruption? Experts say not, explaining that these rises and falls are merely a normal part of the volcanoes life cycle.

It will erupt.

Although most experts agree that the Yellowstone volcano will erupt at some point in the future, they claim there is little evidence of this happening any time soon. Nevertheless bulges in volcanoes are proof or enormous pressures building up beneath the surface and in the case of the Yellowstone these pressures make sober if not alarming reading.

Immense magma reservoir.

It is thought that 5 miles beneath the surface of the Yellowstone lies an immense red hot reservoir of magma around 30 miles long, 20 miles wide, and 6 miles deep. This magma is what powers Yellowstone’s fantastic geysers and hot springs, but it is the pressures associated with this build-up that could one day prove lethal with an explosion of unparalleled proportions that some experts believe would not only obliterate much of North America but push the entire human race to the brink of extinction.

Sooner rather than later?

The main question concerning the Yellowstone is not if it will erupt but when? Geologist Ilya Bindeman thinks this will happen in the near geologic future. But since this undoubtedly means anytime within the next 25,000 years we are left none the wiser regarding the present likelihood. What does worry Bindeman is the near clockwork series of past eruptions that suggest the next one will be sooner rather than later. He warns: "These magmas usually erupt in a very catastrophic way. By comparison, the eruption of Mount St. Helens sent about two cubic kilometres of ash into the atmosphere. These catastrophic types of eruptions send thousands of cubic kilometres of ash skyward.”

The last eruption of the Yellowstone was 600,000 years ago and blasted 1,000 cubic kilometres of volcanic rock into the atmosphere which would have settled as ash over more than half of the United States.

The last super volcano.

Across the world the last eruption of a super volcano was the Toba volcano in Indonesia. This erupted around 75,000 years ago spewing out tremendous quantities of rock and ash and is thought to have reduced global temperatures by up to 21 degrees centigrade.

Worldwide implications.

We see then that the eruption of super volcanoes is on a much more violent scale than normal volcanoes with much wider implications for the world as a whole. Reassuringly scientists at The Yellowstone Volcano Observatory say there is presently no cause for concern with little evidence to suggest that an eruption is imminent. Even if there was there is not much one could do about it. Here as with many other natural hazards we find ourselves wishing that the inevitable day of reckoning will be postponed for as long as possible.

For more on the Yellowstone Super Volcano please go to the following links:

http://news.nationalgeographic.com/news/2001/08/0828_wi reyellowstone.html

http://www.earthside.com/yellowstone.html

Atlantean connection.

Super volcanoes may also throw fresh light on the Atlantis mystery. Amongst those who believe that Atlantis once existed as an Atlantic Island there is a growing belief that it too may have fallen victim to an immense super volcano. It should be understood that super volcanoes are much larger than normal volcanoes and when they erupt, hurl thousands of cubic kilometres of earth, rock, and ash skywards.

A vanished island.

According to the Greek philosopher Plato, Atlantis fell victim to immense volcanic eruptions and within a single day and night disappeared beneath the waves to be forever lost. Until recently such claims may have been regarded as nonsense. However an erupting super volcano would disgorge so much matter it would form an immense magma depression into which a surrounding landmass would quickly submerge. An island in an Ocean would simply vanish. On a continent much of the land would be swamped to form a lake such as can be found in the Yellowstone National Park.

 

Yellowstone Volcano: Is "the Beast" Building to a Violent Tantrum?

StandardNET

August 30, 2001

yellowstone-aerial

When the volcano in Yellowstone National Park blew 6,400 centuries ago, it obliterated a mountain range, felled herds of prehistoric camels hundreds of miles away and left a smoking hole in the ground the size of the Los Angeles Basin.
Modern Yellowstone doesn’t dwell on its cataclysmic past—or its potential for another monster eruption.

Rangers tell people to keep their distance from bison and steaming geysers. But there are no signs, aside from nature’s own bubbling mud pots and geysers, that visitors are wandering through the caldera of one of the largest active volcanoes in the world.

"This is a geologic park, and not many know it," said Robert Smith, a geophysicist at the University of Utah who has spent his career piecing together the story of the Yellowstone volcano. "It’s not a bison park. Not an elk park. It’s a geologic park."

New sensors have allowed researchers to confirm a suspicion that Smith has held for a long time: that the ancient volcano scientists dub "the beast" is a living force. The instruments record a continuing pattern of heaving and bulging and act as an early warning system.

Installed without fanfare and hidden from view, the sensitive devices are an acknowledgment that the past could be prologue, that this seemingly serene plateau could blow so hard it would make the 1980 Mount St. Helens explosion look like a sneeze.

Stepped-Up Monitoring

This summer, Yellowstone was added to the nation’s handful of official volcano observatories. The others, smaller but far better known, are in Hawaii, Alaska, the Cascades, and California’s Long Valley.

The Yellowstone observatory consists of a string of 28 electronic detection stations scattered through the park. Related plans call for at least 100 more monitoring sites.

For Smith, who argued for years that the volcano deserved more attention than it was getting, the observatory is sweet vindication. The beast is finally getting its due.

What took so long for science to put its ear to the ground, given the fact that geophysicists have known for 30 years that Yellowstone was a major volcanic system?

For one thing, Smith said, they couldn’t decide whether the Yellowstone system was still active or in its death throes. For another, it doesn’t look like a volcano.

It’s just too big. From a viewpoint on the north rim of the caldera, a few miles from the Yellowstone River’s Upper and Lower Falls, the southern edge of the caldera is obscured. It’s more than 30 miles (50 kilometers) away—well within the massive park, but lost in the haze.

The last huge eruption was 640,000 years ago. Since then, a series of smaller ones have filled in the caldera "like tubes of toothpaste squeezing out all over the place," Smith said. The 3,000-foot-thick (one kilometer-thick) glaciers of the last Ice Age erased edges of the caldera, which is now a broad, undulating plateau rimmed by mountains.

The Earth has always shaken periodically around Yellowstone. But without the proper monitoring equipment in place, no one knew how often it happened or why. Smith, who has been investigating here for more than 30 years, set up seismometers and found earthquakes by the hundreds.

The Basin and Range country that extends from California to Montana is one of the most seismically active regions east of California’s San Andreas Fault. It is being stretched apart as tectonic plates beneath it move.

But the earthquakes Smith started tracking three decades ago—15,000 between 1973 and 1998, often in swarms—didn’t altogether fit conventional notions of seismicity. There were quakes where you would expect them to occur, along north/south fault lines perpendicular to the stretching. But there were also some along parallel fault lines—activity that seemed to have no relation to the stretching.

Smith started thinking about the quakes in combination with Yellowstone’s famously unstable plumbing. Was it possible that both the quakes and the geysers were products of volcanic action, of underground magma flows?

Hot Spot

Atop a volcano, mountains are pushed up by swelling magma; the subsequent explosion then destroys them and engulfs their remains.

In 1965 a team led by Robert Christiansen of the U.S. Geological Survey mapped the massive caldera and various lava flows in detail while NASA tried out a new remote-sensing technology in the region.

"It was not a surprise it was a young volcano," Christiansen recalled. "It was a surprise it was as young as it is."

He turned to Smith, whose seismic data would reveal whether the volcano was still rumbling. Together, the two men were able to see the system for what it was: a very active and large volcano that had sculpted much of the Northwest.

Smith and Christiansen saw evidence that a huge plume of magma rose from deep within the Earth and bore through the continental plate. As the plate moved southwest, the "hot spot" left a series of what Smith terms "ancient Yellowstones" across a 500-mile (800-kilometer) swath of southern Idaho from Oregon to Montana.

The hot-spot theory was dismissed when it was introduced by Smith in 1973. Accepted wisdom said volcanoes were found at the edges of tectonic plates and that hot spots occur mainly on the seafloor. "It took people a while to catch on," Smith said.

The evidence, ultimately, was incontrovertible.

There was the blasted topography, the layers of lava flows, the misaligned earthquake faults and Yellowstone’s superheated, effervescent plumbing. Only one force was big enough to account for it all: a massive volcano. What Smith still didn’t know was whether it was asleep.

In the mid-1970s, while surveying an old benchmark put into place when the first roads were cut through Yellowstone in 1923, Smith found that the ground had risen three feet (one meter) in five decades.

There could be only one explanation. The volcano was bulging upward. Smith and his students spent two years confirming the observation. By 1979, when he published the findings in the journal Science, even skeptics were becoming convinced that Yellowstone was an active volcano.

The caldera rose an inch a year until 1985. Then a swarm of earthquakes occurred nearby. By 1987 measurements showed that the caldera was falling an inch (2.5 centimeters) a year. In 1995 it started rising again. The caldera is now bulging again, toward the southwest.

Confirmation that the volcano was active was one of the most important factors in getting a new observatory established here. The movement of the volcano also suggests a controversial new idea forcing many geologists to rethink the very definition of hot spots and how they work.

Will It Blow Again?

Until Smith came along, most scientists believed that hot spots originate 1,800 miles (2,900 kilometers) down, at the boundary between the Earth’s core and mantle. The newly revealed geology of Yellowstone suggests that this hot spot might be very shallow, born of the vagaries of heat and changing pressures or some other process yet unknown.

As far as it goes, the scientists work has yet to answer the most important question of all: Will the volcano blow its top again?

New studies by a research team at the University of Wisconsin that analyzed tiny crystals within hardened lava suggest a "dying, but still potent, cycle of volcanism."

Some people believe that the hot spot is moving under the Rocky Mountains, a much thicker and colder part of the continent, and that it will be effectively capped. Others contend that the cap won’t stop the fury of the hot spot.

Smith and Christiansen can’t say for sure, but they know the volcano is not dead. There is no reason, they say, it won’t blow again.

Christiansen doubts the likelihood of another cataclysmic eruption any time soon, but he doesn’t rule out something smaller. Earthquakes, rock slides, and steam explosions from geyser basins are all possible. A blowout on the scale of Mount St. Helens is conceivable, he said, adding: "We need to be prepared."

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