Yellowstone ‘supervolcano’ 2,000 times power of Mount St. Helens
Published: 13 hours ago
Every year, more than 3 million people visit one of America’s most popular tourist attractions, unaware of the tempest that lies just below the surface.
One sign of the tumult occurred this month when oil bubbled up to the surface, damaging a road in Yellowstone National Park, a result of extreme heat from the thermal activity below.
“It basically turned the asphalt into soup,” the park spokesman, Dan Hottle, told USA Today. “It turned the gravel road into oatmeal.”
Road problems caused by excessive underground temperatures are common.
Yellowstone covers nearly 3,500 square miles and contains 10,000 geothermal features, one half of all the known features of that kind in the world. The park also has 300 geysers, the largest concentration in the world. “Old Faithful,” the world’s best known geyser, blasts thousands of gallons of boiling hot water between 100 and 200 feet into the air every 60 to 90 minutes.
What is driving this geologic wonder?
Below the park is what geologists call a “supervolcano,” a massive chamber of molten rock, called magma, that packs tremendous energy.
The Yellowstone Caldera, or cauldron, sits on top of North America’s largest volcanic field. Four hundred miles under the Earth’s surface is a magma ‘hotspot’ that reaches up to just 30 miles below ground level before spreading out over an area of 300 miles across three states.
Over all this sits the volcano.
While most scientists believe the probability of a major eruption is very small, there are signs that have some analysts worried, and most agree the volcano holds catastrophic potential. It could blast 240 cubic miles of ash, rocks and lava into the atmosphere, rendering about two-thirds of the nation immediately uninhabitable, according to some estimates, and plunge the world into a “nuclear winter.”
Meanwhile, Geologists have recently discovered that the Yellowstone supervolcano is twice as big as previously thought.
To put it in perspective, the Mount St. Helens volcanic explosion would be miniscule in comparison to an explosion at Yellowstone, which could pack 2,000 times the power, according to geologists.
An earthquake May 18, 1980, caused the eruption of Mount St. Helens, sending a column of ejecta more than 80,000 feet into the atmosphere.
The blast was so sudden that all the water in nearby Spirit Lake was temporarily displaced and the subsequent landslide sent 600-foot waves crashing into the ridge north of the lake, adding almost 300 feet of debris onto lakebed. Like an inland tsunami, when the water moved back into Spirit Lake, it carried with it thousands of trees blown over by the blast and raised the level of the lake 200 feet.
Hundreds of square miles were reduced to wasteland, causing more than $1 billion in damage, about $2.88 billion in 2014 dollars.
University of Utah Geophysicist Robert Smith first called Yellowstone a “living breathing caldera” in 1979. He now heads the Yellowstone Volcano Observatory at the University of Utah.
“Our best evidence is that the crustal magma chamber is filling with molten rock, but we have no idea how long this process goes on before there either is an eruption or the inflow of molten rock stops and the caldera deflates again,” he said.
Smith insists that even though the volcanic formation is massive, there is absolutely no need to panic.
“We create scenarios. We know roughly what to expect of the patterns of time and space of the earthquakes ground information. Again, acquired from other experiences around the world, we use that to interpret our own data in terms of what the potential threat or risk might be,” he said.
Smith has said that he doesn’t even like the term “supervolcano.”
“I prefer to use the term “hotspot,” because it reflects a zone of concentrated and active volcanism.”
According to the USGS website:
Although it is possible, scientists are not convinced that there will ever be another catastrophic eruption at Yellowstone.
Given Yellowstone’s past history, the yearly probability of another caldera-forming eruption could be calculated as 1 in 730,000 or 0.00014 %. However, this number is based simply on averaging the two intervals between the three major past eruptions at Yellowstone – this is hardly enough to make a critical judgment. This probability is roughly similar to that of a large (1 kilometer) asteroid hitting the Earth. Moreover, catastrophic geologic events are neither regular nor predictable.
As even the USGS alluded, there may be no warning of an eruption of the supervolcano. Scientists at the European Synchrotron Radiation Facility, ESRF, in Grenoble, France, concluded that supervolcanos can erupt without earthquakes or any other warnings. The sheer pressure of lava in the dome, they say, can cause an eruption without any earthquakes beforehand.
High impact, now probability
Smith and Jamie Farrell, also of the University of Utah, believe that Yellowstone erupting is a high-impact but low-probability scenario.
However, there have been signs that the magma beneath the surface has become more active than it has been before.
The supervolcano underneath Yellowstone has been rising at a record rate since 2004. Its floor has gone up three inches per year for the last three years alone, the fastest rate since records began in 1923.
Smith told National Geographic: “It’s an extraordinary uplift, because it covers such a large area and the rates are so high”.
Geologists call Yellowstone “their laboratory” and are constantly monitoring the thermal and seismic activity below the park’s surface.
Hawaii and Iceland are other examples of geologic hot spots, but Yellowstone is the only hot spot located underneath land rather than sea, which has made it easier to study.
Smith and his team have set up a series of sensors around the park so that they can closely monitor the volcano’s vital signs. They measure ground movement and record the frequent earthquakes that occur in the area. Their research has uncovered amazing facts about the activity below.
Less than five miles below the surface is a shallow reservoir of solid rock and magma. Below this is a much larger 13.5 cubic mile plume of magma, the engine that fuels the thermal pools and geysers in Yellowstone.
While Smith insists there is no need to panic, not all scientists are in agreement.
It is the rising of the volcano floor that has some scientists worried. They believe that an eruption is closer than what some of the experts say.
A team of researchers with the U.S. Geological Survey has also found that a large amount of ancient helium is constantly being released in Yellowstone National Park, the result, they suggest in their paper published in the journal Nature, of a magma hot spot releasing previously trapped gasses.
These helium isotopes, helium-3/helium-4, are critical tracers in the Earth sciences, where they are used to trace the activity of the Earth’s mantle. Yellowstone National Park is famous for its high helium-3/helium-4 isotope ratio and is commonly cited as evidence for a deep mantle source for the Yellowstone hotspot. An increase in the presence of these isotopes is also cited as preceding increased volcanic activity.
In one instance, the underwater volcano El Hierro, near the smallest of Spain’s Canary Islands, showed increased volcanic activity over the course of seven months in 2011 and 2012. The helium-4 filtrated up through the island’s soil and groundwater. Eventually, a spectacular plume appeared off the southern coast of the island, a sign that the El Hierro volcano had finally erupted.
The team’s analyses show that as the El Hierro volcano became more active, the crust fractured and helium, mostly from the mantle, flowed to the surface. As the actual eruption began, gas flow at the surface increased dramatically, and gas pressure beneath the island dropped. As seismic activity at El Hierro picked up again, the crust fractured and helium-4 became a larger component of the total helium released on the island.
The quantity of helium-4 coming off of Yellowstone is hundreds to thousands of times greater than it should be – a sign that there is a marked increase in volcanic activity in the area. The report shows that by “combining gas emission rates with chemistry and isotopic analyses, the crustal helium-4 emission rates from Yellowstone exceed by orders of magnitude any conceivable rate of generation within the crust.”
This is activity that has not been seen before in the lifetime of anyone alive today.
Just what would a Yellowstone eruption look like? Smith’s team has developed several scenarios, and every one of them is bleak.
Complete and incomprehensible devastation
According to Smith, in his book “Windows into the Earth,” the “devastation would be complete and incomprehensible.”
“Before the super eruption, large earthquakes would likely swarm the surrounding areas until the huge blast that would erase Yellowstone completely off the map.”
Farrell said it would be a “global event.”
“There would be a lot of destruction and a lot of impacts around the globe,” he said.
Most scientists agree that when the Yellowstone volcano does erupt, the results will be catastrophic.
By some estimates, 87,000 people would die immediately.
Thousands of cubic miles of red-hot volcanic ash would cover the Western United States and shoot into the atmosphere.
Light from the sun would be blocked, making global temperatures plummet into a prolonged “nuclear winter.”
The entire grain harvest of the Great Plains would virtually disappear in a matter of hours, since it would be coated in ash, threatening a substantial portion of the world’s food supply.
If temperatures plummet by the 21 degrees they did after the Toba volcano eruption in Sumatra of ancient times, the Yellowstone supervolcano eruption could truly be an extinction-level event
It is estimated that a full-blown eruption of Yellowstone could leave two-thirds of the United States completely uninhabitable.
Just before the eruption, the pressure underground will build and the magma will rise, forcing its way out of the ground, sending lava and sulfuric acid gas into the air. The blast will also propel ash up to 20 miles into the atmosphere where the easterly jetstream would carry it as far away as Europe in as quickly as three days.
The gas, the source for acid rain, would remain in the atmosphere for years, screening out sunlight, causing global temperatures to drop and killing crops for years afterward.
Even a small amount of ash would close airports, cause damage to vehicles and houses, and contaminate water supplies.
The ash resulting from the 2010 eruption of the Eyjafjallajökull volcano in Iceland caused the largest air traffic shutdown since World War II.
The book “Supervolcano” includes an in-depth, fictional account of a super eruption.
According to the book:
Within days and weeks of the supereruption, the suspension of air routes, the inability to bring cargo in and out of the most deeply affected areas, and the virtual decimation of the Grain Belt, the area of our nation responsible for the vast majority of our grain food sources, all contribute to a growing sense of desperation and panic among survivors anxious to find food.
It only takes 0.04 inches of ash to close airports, and the wide swath of blanketed ash would literally shut down every major and minor airport for thousands of miles across the country.
Because even a small amount of ash can clog an engine, road transportation is heavily curtailed, and trucks and machines normally engaged in the moving of supplies from one state to another find themselves immobilized.
Electrical equipment shorts out, and wide areas experience power outages and rolling blackouts, rendering communication via computers and phones obsolete.
The book also describes subsequent food riots, contaminated water and an outbreak of violence and anarchy. Although North America would be the hardest hit, the explosion would affect the entire planet.
‘$3 trillion damage’
It is truly a “doomsday” scenario.
In such a scenario for North America, according to Doug Bausch, a senior scientist at FEMA, $3 trillion in “direct economic damage” is a reasonable estimate.
It’s about 20 percent of the U.S. Gross Domestic Product.
Spewing lava far into the sky, a cloud of plant-killing ash would fan out and dump a layer 10 feet deep up to 1,000 miles away.
Two-thirds of the U.S. could become uninhabitable as toxic air sweeps through it, grounding thousands of flights and forcing millions to leave their homes.
Smith believes that rather than an eruption, the more immediate threat is earthquakes and smaller eruptions, since the probability of one of those instances occurring is much higher.
“It’s an extraordinary uplift, because it covers such a large area and the rates are so high. At the beginning, we were concerned it could be leading up to an eruption.”
Just when and how big is anyone’s guess.
Michio Kaku, American television personality and theoretical physicist with at the City College of New York, said it best.
“All you can do is run.”