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Post by Watchman on Jun 29, 2005 17:15:57 GMT -5
Area professors to visit, research 'super volcano'
By Tom Venesky, Staff Writer
Standing in the middle of one of the most volatile volcanic regions on the planet, Wilkes University professors Dr. Sid Halsor and Dr. William Toothill monitor the ground for millimeters of movement to determine if the liquid rock below is going to erupt.
On Saturday, Halsor and Toothill left for Yellowstone National Park in Montana, where they will join staff from several universities around the country to research the Yellowstone caldera.
The caldera is a large crater, 31 miles across, that formed from released volcanic material over thousands of years. Halsor said the caldera is referred to as a "super volcano," one that erupts 1,000 times more ash than a normal eruption.
"These are enormous volcanic events," Halsor said.
Halsor and Toothill have conducted GPS research at the caldera since 1999.
Research permits in the park are difficult to obtain, Halsor said, adding they were invited to participate by head researcher Dr. Craig Chesner of Eastern Illinois University.
Only a dozen universities from around the country are involved with the research.
"As a scientist this is a unique opportunity. Only a handful of people in the world do this type of research, and we feel privileged to be a part of that," Toothill said. "Being involved in this is an indicator of the quality of the GPS program at Wilkes."
Past events show the caldera erupts every 600,000 years. The last eruption was 630,000 years ago, Halsor said, and the current research shows some interesting developments.
"At Yellowstone, what we're seeing is one year the ground may rise up and next year it may subside a few millimeters or centimeters," Halsor said. "We're watching a trend that shows a larger uplift sustained over several years. If we continue to see this accelerated uplift, it might be the early stages (of an event).
The last caldera eruption spewed 1,000 cubic kilometers of volcanic material into the air, Halsor said.
Although the pattern or eruptions indicate the caldera is ready to blow again, Halsor cautioned it probably won't be in our lifetime.
"It would not be surprising if another large eruption were to occur at Yellowstone within the next few 1,000 years," he said. "The overall consensus is there's nothing currently indicating the caldera is on the path of erupting in a big way, but if it were to begin along that path it wouldn't be a surprise to the geological community."
Several Wilkes students accompanied Halsor and Toothill for the research, which continues until June 26.
Toothill described the work as "intense," complete with around the clock research and wildlife encounters.
"We monitor the caldera all day and all night, and there's some unique problems with wildlife," he said. "You have to be very alert because some of the monitoring sites are in grizzly bear habitat."
Collected data is brought back to Wilkes to be processed and compared to past years' research.
"It's very exciting to be involved with a community of geologists doing research at one of the most volatile volcanic systems on the planet," Halsor said. "Being able to apply our mode of GPS technology to this unparalleled ecosystem is a privilege."
©The Citizens Voice 2005
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Post by kjax on Dec 15, 2005 6:35:34 GMT -5
Not sure if you've ever seen a map of what an eruption of that volcano might look like- it's interesting, the projected devastation that would result. I'm on the other end of the state, and would be burried with the lava that would spew forth if it erupted as some speculate. Makes most of the other volcanos in the US rather pale in comparison. If I remember right there are 2 or 3 "super volcanos" in the US.
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Post by Watchman on Mar 2, 2006 13:04:48 GMT -5
Supervolcano Raises Yellowstone, Fuels Geysers, Study Says Scott Norris for National Geographic News
March 1, 2006 Molten rock flowing beneath Yellowstone has been causing the national park to rise and fall, scientists say.
Periodic uplifting and settling has occurred here over the last 15,000 years.
A new model helps explain the latest episode of rapid surface rise and increased geyser activity—from 1997 to 2003—in the volcanically active region in the western United States.
Much of Yellowstone National Park lies in the crater of a massive volcano, formed in a landscape-altering eruption 640,000 years ago. The crater, or caldera, measures some 28 miles wide by 47 miles long (45 by 75 kilometers).
Subsequent lava flows—most recently 70,000 years ago—filled in much of the blasted-out crater, disguising the area's volcanic identity (related site: volcano photos, facts, and virtual eruptions).
Since the 1970s scientists have known that the Yellowstone volcano remains highly active. (See "Yellowstone Volcano: Is 'the Beast' Building to a Violent Tantrum?" [2001].)
But the precise relationship between volcanic activity deep underground and Yellowstone's well-known network of geysers and other geothermal features has long been a puzzle for geologists.
Now a study by scientists with the U. S. Geological Survey (USGS) and the Yellowstone Volcano Observatory attributes changes in both surface terrain and geyser behavior to flows of magma, or molten rock, 9 miles (15 kilometers) below the Earth's surface.
"We're not sure yet if this is a normal episode or not," said Charles Wicks, a geologist at the USGS Western Region headquarters in Menlo Park, California.
Wrinkles and Cracks
Using satellite-based radar, Wicks and his colleagues were able to map small changes in surface elevation continuously across a wide area.
The new, detailed view of the Yellowstone crater shows a surface in constant motion, rising and falling in different locations and over fairly short intervals of time. From earlier surveys, scientists know that the caldera floor raised about 7 inches (18 centimeters) from 1976 to 1984 and then settled back about 5.5 inches (14 centimeters) from 1985 to 1995.
The new report, to be published in tomorrow's edition of the journal Nature, focuses on an isolated area along the north rim of the crater that continued to rise while the crater floor was sinking.
This localized uplift raised the ground level about 5 inches (13 centimeters) from 1997 to 2003.
"This was something new," Wicks said. "We had never seen uplift under the caldera rim before."
At the same time thermal activity in and around the Norris Geyser Basin, near the uplifting-rim area, began moving into high gear.
Steamboat Geyser, the world's largest, broke a nine-year silence with a series of eruptions from 2000 to 2003.
Park officials had to close some hiking trails due to increasing ground temperatures, and in 2003 a line of new steam vents appeared, roaring like jet engines.
Wicks and his colleagues believe that a pulse of volcanic magma moving horizontally underground caused the complex rippling of the land surface and the unusual hydrothermal displays.
A New Model
The researchers' theory is based on a mathematical model that helps explain the pattern of lifting revealed by the radar imaging.
The land's rise and fall over time, they say, can be attributed to variation in what may be a continuous flow of molten basalt. Basalt is cooled, hardened magma.
Wicks believes that in the 1997-to-2003 episode, an unusually large pulse of magma rose from deep underground and spread outward just beneath the caldera surface.
"As it spreads it looks for a way out," Wicks said. "A system of faults under the north rim provides a way for the magma to exit the caldera."
Outward movement of the magma pulse would cause the caldera floor to rise and then fall back, exactly as observed.
The continuing uplift of the caldera rim can be explained by the restricted size of the magma's exit route.
Wicks thinks a sort of underground bottleneck caused part of the north rim to continue rising. Forced through a narrowing passage, he says, the magma exerted a pressure that caused the rim to rise.
Uplift in this relatively confined area may have opened new underground passages for steam and superheated water, causing the unusual geyser activity.
"It's like bending a slab of clay. You see cracks form on the upper surface," Wicks said.
Park geologist Henry Heasler said that, while the new study is compelling, further tests of the model are needed.
"What they have nailed is that an intrusion from the caldera up to the Norris area matches the ground deformation pattern," Heasler said. "It's a fascinating paper, but there are still competing hypotheses."
For example, the surface changes may have been driven by flows of hot water and gas rather than magma.
Heasler said one way to test this would be by taking precise temperature measurements at the land surface, which he and others plan to carry out.
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Post by Watchman on May 23, 2006 13:10:19 GMT -5
MIcroscopic crystals of volcanic ash are revealing surprising clues about the world's most devastating eruptions
By Ilya N. Bindeman Lurking deep below the surface in California and Wyoming are two hibernating volcanoes of almost unimaginable fury. Were they to go critical, they would blanket the western U.S. with many centimeters of ash in a matter of hours. Between them, they have done so at least four times in the past two million years. Similar supervolcanoes smolder underneath Indonesia and New Zealand. A supervolcano eruption packs the devastating force of a small asteroid colliding with the earth and occurs 10 times more often--making such an explosion one of the most dramatic natural catastrophes humanity should expect to undergo. Beyond causing immediate destruction from scalding ash flows, active supervolcanoes spew gases that severely disrupt global climate for years afterward.
Needless to say, researchers are eager to understand what causes these giants to erupt, how to predict when they might wreak havoc again, and exactly what challenges their aftermath might entail. Recent analysis of the microscopic crystals in ash deposits from old eruptions has pointed to some answers. These insights, along with improved technologies for monitoring potential disaster sites, are making scientists more confident that it will be possible to spot warning signs well before the next big one blows. Ongoing work hints, however, that supervolcano emissions could trigger alarming chemical reactions in the atmosphere, making the months following such an event more hazardous than previously suspected.
Almost all volcano experts agree that those of us living on the earth today are exceedingly unlikely to experience an active supervolcano. Catastrophic eruptions tend to occur only once every few hundred thousand years. Yet the sheer size and global effects of such episodes have commanded scientific attention since the 1950s.
Early Awe One of geologists' first discoveries was the existence of enormous circular valleys--some 30 to 60 kilometers across and several kilometers deep--that looked remarkably similar to the bowl-shaped calderas located atop many of the planet's most well-known volcanoes. Calderas typically form when the chamber of molten rock, or magma, lying under a volcanic vent empties out, causing the ground above it to collapse. Noting that these calderalike valleys sit close to some of the earth's largest deposits of volcanic rocks laid down during a single event, those early investigators realized they were seeing the remnants of volcanoes hundreds or even thousands of times larger than the familiar Mount St. Helens in Washington State. From the extreme scale of the calderas and the estimated volume of erupted material, researchers knew that the magma chambers below them had to be similarly monstrous.
Because the thick continental crust and heat sources needed to create such massive magma chambers are rare, supervolcanoes themselves are also uncommon. In the past two million years, a minimum of 750 cubic kilometers of magma has exploded all at once in only four regions: Yellowstone National Park in Wyoming, Long Valley in California, Toba in Sumatra and Taupo in New Zealand. The search for similarly large eruptions continues in other areas of thick continental crust, including in western South America and far eastern Russia.
By the mid-1970s, investigations of past events revealed some ways that the chambers can form and become dangerous. Under the surface of Yellowstone, the North American tectonic plate is moving over a buoyant plume of warm, viscous rock rising through the mantle, the 2,900-kilometer-thick layer of the earth's interior that is sandwiched between the molten core and the relatively thin veneer of outer crust. Functioning like a colossal Bunsen burner, this so-called hot spot has melted enough overlying crust to fuel catastrophic eruptions for the past 16 million years. In Toba, the source of the chamber is different. That region lies above a subduction zone, an area where one tectonic plate is slipping under another; the convergence produces widespread heating, mainly through partial melting of the mantle above the sinking plate.
No matter the heat source, pressure in the magma chambers builds over time as more magma collects under the enormous weight of overlying rock. A supereruption occurs after the pressurized magma raises overlying crust enough to create vertical fractures that extend to the planet's surface. Magma surges upward along these new cracks one by one, eventually forming a ring of erupting vents. When the vents merge with one another, the massive cylinder of land inside the ring has nothing to support it. This "roof" of solid rock plunges down--either as a single piston or as piecemeal blocks--into the remaining magma below, like the roof of a house falling down when the walls give way. This collapse forces additional lava and gas out violently around the edges of the ring.
Fingerprinting Eruptions Yet mysteries remained. Notably, as researchers soon realized, not every large magma chamber will necessarily erupt catastrophically. Yellowstone, for example, is home to three of the world's youngest supervolcano calderas--they formed 2.1 million, 1.3 million and 640,000 years ago, one nearly on top of the other--but in the gaps between these explosive events, the underlying chamber released similar volumes of magma slowly and quietly. Why magma sometimes oozes slowly to the surface is still uncertain.
A look at the composition of tiny crystals trapped inside erupted lava and ash at Yellowstone has suggested a partial answer, by providing new insight into how magma forms. For decades, geologists assumed that magma sits as a pool of liquefied rock for millions of years at a time and that each time some of it pours out onto the earth's surface, new liquid rises up from below to refill the chamber immediately. If that conception were correct, one would expect many more catastrophic, voluminous eruptions, because it is mechanically and thermally infeasible to keep monster magma bodies in the crust without emptying them frequently.
The old idea was based largely on so-called whole-rock analyses in which researchers would obtain a single set of chemical measurements for each fist-size piece of volcanic rock they collected. Those data provided important general patterns of magma evolution, but they were insufficient for determining the age of the ejected magma and the depth at which it formed.
Every chunk of rock is actually made up of thousands of tiny crystals, each with its own unique age, composition and history. So when technological advances made it possible in the late 1980s to analyze individual crystals with good precision, it was like being able to read individual chapters in a book rather than relying on the jacket blurb to explain the story. Investigators began to see that some crystals--and thus the magmas in which they originally formed--arose much earlier than others, for instance, and that some formed deep underground, whereas others formed near the earth's surface.
During the past 10 years, geochemists have been paying particular attention to an especially durable type of volcanic crystal called zircon. Knowing that zircons can withstand extreme changes in heat and pressure without compromising their original composition, a few researchers--among them John W. Valley of the University of Wisconsin-Madison--have been using them to study the early evolution of the earth's crust [see "A Cool Early Earth?" by John W. Valley; Scientific American, October 2005]. When I joined Valley's team as a postdoctoral fellow in 1998, we used Yellowstone zircons to trace the history of their parent magma--which in turn revealed important clues about how the volcano may behave in the future.
The first step was to measure the ratios of different forms of oxygen in zircons from the youngest Yellowstone supereruption--which after exploding 640,000 years ago gave rise to the Lava Creek tuff, a fossilized ash deposit 400 meters thick in some places--as well as younger deposits that were expelled during milder eruptions since then. When I finished my initial analyses, Valley and I were both surprised to see that oxygen composition of those zircons did not match that of deep, hot mantle, as would be expected if drained chambers always filled from below. Zircons born of mantle-derived magmas would have had a distinctive signature: as elements that are dissolved in magmas come together to form a zircon, that crystal takes on a notably high proportion of oxygen 18, a heavy isotope of oxygen that has 10 neutrons in its nucleus instead of the usual eight.
Valley and I saw immediately that the magma must have originated in rock once near the earth's surface. The zircons we studied were depleted in oxygen 18 relative to the mantle, and such depletion occurs only if the crystals formed from rocks that interacted with rain or snow. We thus suspected that the collapsed roof rock from one of the two oldest Yellowstone supereruptions must have melted to form the bulk of the magma that was ejected during the younger Lava Creek catastrophe and smaller eruptions since. This hypothesis gained strength when we learned that the ages of the zircons from post-Lava Creek eruptions span the entire two-million-year duration of Yellowstone volcanism. Such old zircons could exist in the youngest ash only if they originated in material that was ejected during the oldest eruptions and if that material later collapsed back into the magma chamber and remelted to help fuel the youngest eruptions.
Our findings mean that scientists can now expect to make certain predictions about how the Yellowstone supervolcano, and possibly those elsewhere, will behave in the future. If a new round of small, precursor eruptions begins in Yellowstone--and they usually do so weeks to hundreds of years before a catastrophic explosion--testing the oxygen fingerprint of those lavas and the ages of their zircons should reveal what type of magma is abundant in the chamber below. If the next eruption is depleted in oxygen 18, then it is most likely still being fed by stagnant remnants of the original magma, which by now is probably more of a thick crystal mush than an explosive liquid. On the other hand, if the new lava carries the fingerprint of fresh magma from the mantle and does not contain old zircons, then it very likely came from a large volume of new magma that has filled the chamber from below. Such findings would imply that a new cycle of volcanism had commenced--and that the newly engorged magma chamber had more potential to explode catastrophically.
Immediate Aftermath Tiny crystals and their isotopic signatures have also revealed surprises--good and bad--about the aftermath of supereruptions. One of the best-studied examples of supervolcano aftermath is the Bishop tuff, a volcanic layer tens to hundreds of meters thick that is exposed at the earth's surface as the Volcanic Tablelands in eastern California. This massive deposit represents what is left of the estimated 750 cubic kilometers of magma ejected during the formation of the Long Valley supervolcano caldera some 760,000 years ago.
For decades, many geologists assumed that a series of distinct eruptions over millions of years must have occurred to produce the extensive Bishop tuff. But careful studies of microscopic, magma-filled bubbles trapped inside tiny crystals of quartz tell a different story. The rate at which magma leaves a chamber depends primarily on two factors: the magma's viscosity, or ability to flow, and the pressure difference between the chamber and the earth's surface. Because the pressure inside a bubble matches that of the chamber where the magma formed, the bubble acts like a mini version of the chamber itself.
Aware of this correspondence, Alfred Anderson of the University of Chicago and his colleagues studied the size of the bubbles under a microscope to estimate how long it took the magma to leak out. Based on these and other experiments and field observations from the 1990s, geologists now think that the Bishop tuff--and probably most other supererupted debris--was expelled in a single event lasting a mere 10 to 100 hours.
Since that discovery, investigators have had to modify their reconstructions of supervolcano eruptions. Here is what they now generally expect from an event the scale of those that struck Long Valley and Yellowstone: Instead of a slow leak of red-hot lava as is seen creeping down the sides of Kilauea Volcano in Hawaii, these eruptions feature supersonic blasts of superheated, foamlike gas and ash that rise buoyantly all the way into the earth's stratosphere, 50 kilometers high.As the land above the magma chamber collapses, immense gray clouds called pyroclastic flows burst out horizontally all around the caldera. These flows are an intermediate stage between lava and ash, so they move extremely rapidly--up to 400 kilometers an hour, some sources say; cars and even small airplanes would have no chance of outrunning them. These flows are also intensely hot--600 to 700 degrees Celsius--so they burn and bury everything for tens of kilometers in every direction.
As bad as the pyroclastic flows are, the ash injected into the atmosphere can have even more far-reaching consequences. For hundreds of kilometers around the eruption and for perhaps days or weeks, pale-gray ash would fall like clumps of snow. Within 200 kilometers of the caldera, most sunlight would be blocked out, so the sky at noon would look like that at dusk. Homes, people and animals would be buried, sometimes crushed. Even 300 kilometers away, the ash could be half a meter thick; mixed with rain, the weight would be plenty sufficient to collapse roofs. Less ash than that would knock out electrical power and relay stations. As little as a millimeter, which could well dust the ground halfway around the globe, would shut down airports and dramatically reduce agricultural production.
Only gradually would rain (made acidic by volcanic gases) wash away the thick blanket of ash. And because volcanic rock and ash float, it would clog major waterways. Transportation along big rivers could grind to a halt. Indeed, recent oil drilling in the Gulf of Mexico struck a surprisingly thick layer of supervolcanic debris near the Mississippi Delta--more than 1,000 miles from its source in Yellowstone. Only by floating downriver and then sticking to sediment that sank to the ocean bottom could that amount of debris have accumulated from a volcano so far away.
The Long Haul Investigators have reason to believe that other consequences, arising from the great volumes of problematic gas expelled into the upper atmosphere, would also transpire and could persist for many years. New work suggests that some of these outcomes may not be as bad as once feared but that others may be worse. Once again, looking at the composition of small by-products from past eruptions has been illuminating.
Of the varied gases that make up any volcanic eruption, sulfur dioxide (SO2) causes the strongest effect on the environment; it reacts with oxygen and water to produce tiny droplets of sulfuric acid (H2SO4). These droplets are the main sun-blocking source of the dramatic climatic cooling that would grip the planet in the wake of a supereruption. Knowing that the planet's hydrological cycle takes months or years to fully wash away the acid droplets, many researchers made apocalyptic estimates of "volcanic winters" lasting decades, if not centuries. But in recent years other investigators have uncovered evidence that drastically reduces that calculation.
Almost always, traces of the sulfuric acid produced after large volcanic eruptions are trapped in snow and ice as the acid precipitates out of the contaminated atmosphere. In 1996 investigators studying ice cores from Greenland and Antarctica found the sulfuric acid peak that followed the supereruption of Toba 74,000 years ago. That eruption ejected 2,800 cubic kilometers of lava and ash and reduced average global temperatures by five to 15 degrees C. The consequences of such a chill were undoubtedly severe but did not last as long as once thought: sulfuric acid in the ice rec-ord disappeared after only six years; some researchers suggest that it vanished even earlier.
That volcanic winters are probably shorter than expected is the good news. But a new method developed in the past five years for studying the composition of the oxygen atoms in the volcanic acid rain is revealing an entirely different, alarming sign about the long-term effects of sulfur dioxide in the atmosphere. For SO2 to become H2SO4, it must be oxidized--in other words, it must acquire two oxygen atoms from other compounds already existing in the atmosphere. Exactly which compounds play the key role is a hotly debated topic of current research, so when I started working with John M. Eiler as a staff scientist at the California Institute of Technology in 2003, he and I looked for evidence in my samples of ashes from the prehistoric Yellowstone and Long Valley eruptions.
We began our analyses with a focus on a particularly efficient oxidant, ozone. Ozone is a gas molecule made up of three oxygen atoms best known for shielding the earth from the sun's dangerous ultraviolet rays. Because of rare chemical transformations that certain gases undergo in the presence of that intense solar radiation, ozone is characterized by an anomaly in its so-called mass-independent oxygen isotope signature, which in simple terms can be thought of as an excess of oxygen 17.
When ozone or any other oxygen-rich molecule in the stratosphere interacts with SO2, it transfers its oxygen isotope signature to the resulting acid--that is, the oxygen 17 anomaly persists in the new acid. In 2003 geochemists at the University of California, San Diego, found the first evidence that this signature is also preserved in the oxygen atoms of the acid that later falls as rain and in the sulfate compounds that form as the acid rain reacts with ash on the ground.
The oxygen 17 excess and other chemical patterns that we found in sulfate from the Yellowstone and Long Valley ash samples thus implied that significant amounts of stratospheric ozone were used up in reactions with gas from the supereruptions in those regions. Other researchers studying the acid layers in Antarctica have demonstrated that those events, too, probably eroded stratospheric ozone. It begins to look as if supervolcano emissions eat holes in the ozone layer for an even longer period than they take to cool the climate.
This loss of protective ozone would be expected to result in an increased amount of dangerous ultraviolet radiation reaching the earth's surface and thus in a rise in genetic damage caused by rays. The magnitude and length of the potential ozone destruction are still being debated. Space observations have revealed a 3 to 8 percent depletion of the ozone layer following the 1991 eruption of Mount Pinatubo in the Philippines. But what would happen after an event 100 times larger? Simple arithmetic does not solve the problem, because the details of atmospheric oxidation reactions are extremely complex and not fully understood.
Scientific techniques for studying and monitoring volcanoes of all sizes are developing with all deliberate speed. But no matter how much we learn, we cannot prevent an eruption. And what can be said about the aftermath of the most catastrophic occurrences is still speculative at best. The good news, though, is that researchers now know enough about the sites of possible eruptions to predict with reasonable assurance that no such catastrophe will happen anytime soon
© 1996-2006 Scientific American, Inc. All rights reserved
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Post by Watchman on Dec 4, 2006 14:58:53 GMT -5
Scientists Want Improved Monitoring Of Supervolcano Yellowstone National Park
Proposal: Wire park to predict volcanic rumbling By MIKE STARK Of The Gazette Staff
Few of the roars and rumblings of Yellowstone National Park can be felt underfoot.
But Yellowstone, one of the largest active volcanic systems in the world, is plenty busy, and geologists say more needs to be done to track earthquakes and help predict volcanic eruptions, hydrothermal explosions and other potentially dangerous events.
The U.S. Geological Survey has outlined an ambitious - though unfunded and unapproved - road map for wiring Yellowstone over the next decade to keep better tabs on its geologic life.
Jake Lowenstern, a USGS geologist and head of the Yellowstone Volcano Observatory, said the plan is meant as a starting point for launching discussions about how best to monitor the park.
"It's our way of thinking through what sort of techniques would be useful ... what we do and why and then where do we fall short and how we might improve," Lowenstern said.
The proposal suggests upgrades in Yellowstone's seismic network, more gauges to monitor streams and potentially dangerous gases, Global Positioning System stations that help predict ground-splitting explosions, and even instruments hundreds of feet below the ground to monitor groundwater, magma and shifting rocks.
The place is worth watching.
In the past 2 million years, Yellowstone has launched three of the largest volcanic eruptions on the planet. Another major eruption of what some have called a "supervolcano" has been the topic of much speculation in recent years.
"In terms of knowing whether an eruption is going to happen, we already have a pretty good system," Lowenstern said.
But geologists say at least equal attention should be paid to hydrothermal explosions that, aside from earthquakes and landslides, pose the greatest threat. Probably at least one small, rock-tossing explosion happens in Yellowstone each year, according to the USGS. At least 20 large craters in the park were made by explosions over the last 15,000 years that erupted from boiling groundwater just below the surface.
About 2,000 earthquakes also shake the park each year. Most of them are never felt, but the magnitude 7.5 earthquake at Hebgen Lake in 1959 - the largest recorded in the interior West - killed 28 people and caused extensive damage.
"All (of those) geologic events can occur again at Yellowstone and some likely will within the coming decades," says the USGS plan.
Yellowstone's volcanic system was classified as a "high-threat" system by the federal government in a report last year that noted the park doesn't have enough gauges and gadgets to keep track of it.
Upgrading the system would help detect "subtle, precursory changes that are likely to occur before hazardous events" so people can be given plenty of notice, the USGS plan said.
There are already 26 seismic stations in Yellowstone. Satellites, GPS stations and other instruments also monitor its movements.
One of the shortcomings of the current system is that in a large earthquake, the instruments might be so disrupted they couldn't faithfully record what's going on. Some of the technology is also outmoded - much of it is analog, not digital - and the park doesn't have a redundant system that would allow important geologic data to be relayed outside the park in the case of a large-scale event.
Any new instruments, including those buried in the ground, would need approval from the National Park Service. Though there has been talk of putting more devices in the backcountry, Lowenstern said USGS tries to be as unobtrusive as possible.
"A lot of what we've done is try to put as many instruments as we can in places that are already developed," he said.
There is already funding to install five "strain meters" in Yellowstone over the next three years. Set 300 to 600 feet below the surface, the super-sensitive instruments can detect slight movements in underground rocks.
Copyright © The Billings Gazette, a division of Lee Enterprises.
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Post by Watchman on Dec 18, 2006 16:06:24 GMT -5
upervolcano Yellowstone Domes Rising At 'Really Pronounced' Pace
By MIKE STARK Of The Gazette Staff
Parts of the collapsed, restless volcano in Yellowstone National Park are swelling faster than has ever been recorded.
Geologists from the University of Utah say two domes inside the Yellowstone caldera have steadily inflated at two to three times the rate as some of the most rapid movements recorded between 1923 and 1984.
"We've gone to this really pronounced, and I would say unprecedented, uplift of the caldera," said Bob Smith, a Utah geologist and one of the leading researchers into Yellowstone's busy volcanic life.
Smith presented some of the new findings Wednesday to the American Geophysical Union meeting in San Francisco.
Today, Smith is scheduled to present new information about the vast, fiery hot spot that has fueled Yellowstone for millions of years. One finding is that the tilting plume extends at least 390 miles below the surface.
The new research, including discussion of the origin and evolution of the Yellowstone hot spot, may help put an end to several years of debate about what kind of plume underlies the park.
Like a piece of paper moving over a candle, the Earth's crust has drifted over the hot spot for millions of years, destroying mountains and leaving a 300-mile-wide valley known as the Snake River Plain in Idaho.
The activity had a significant role in shaping landscapes in the West, from drainages and valleys to seismic drama playing out beneath the surface.
"It's had a really profound effect over a much larger area than just Yellowstone," Smith said.
Yellowstone's geology was a hot topic at the AGU meeting. More than 60 presentations touched on the park, whether it was looking at the diet of ancient wolves or activities of helium isotopes.
In recent years, much attention has been focused on so-called "huffing and puffing" of the Yellowstone caldera, the huge collapsed volcano that stretches across the park's middle.
The caldera has been rising and falling for at least 15,000 years, sometimes swinging more than 10 feet.
Portions of the caldera rose more than 3 feet between 1923 and 1984 and then dropped nearly 8 inches from 1985 to 1995. Measurements in 1995 and 1996 showed it rising again before starting to fall in 1997.
The latest upward motion has been unusual for its speed.
Using data collected on the ground and from satellites, scientists say the Mallard Lake Dome, west of Yellowstone Lake's West Thumb, has inflated by 4 centimeters a year since the middle of 2004, while the Sour Creek Dome north of Fishing Bridge has increased by about 6 centimeters a year. (One inch is 2.54 centimeters.)
Smith said the activity may be spurred by an infusion of magma from below that's heating up fluids and causing the ground to bulge.
"It's like inflating the balloon but the balloon is capped," Smith said. "Eventually that fluid's got to go somewhere."
While most of the caldera has been inflating, another nearby area has been falling.
A newly discovered bulge just outside the caldera, near Norris Geyser Basin, has fallen by about an inch since 2004.
But in the preceding six years - from 1997 to 2003 - the dome grew by about 5 inches and may have triggered some of the unusual activity at Norris, including a sudden rise in temperatures, the formation of explosive new steam vents and the reawakening of Steamboat geyser, the world's tallest.
When the dome, called the North Rim Uplift, began deflating again, temperatures at Norris dropped, Steamboat stopped erupting and the steaming vents at nearby Nymph Lake died down.
The below-ground connections between the ups and downs at Norris and domes inside the caldera are still unknown.
And what it all adds up to in the big picture is also unclear - except that Yellowstone continues to be geologically active and few things stay static for long.
In recent years, the possibility of a large volcanic eruption has been a popular media topic, but Smith said the scenario seems overhyped. A more likely possibility would be a large earthquake, he said, noting that the most powerful quake in the interior Western United States happened at Hebgen Lake on Aug. 17, 1959.
"It's a much higher risk," he said.
Copyright © The Billings Gazette, a division of Lee Enterprises.
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Post by Watchman on Mar 2, 2007 18:59:43 GMT -5
Sitting on a tripod, a Global Positioning System (GPS) antenna, powered by portable solar-energy panels, measures gradual movements of Earth's crust in Hot Springs Basin, Yellowstone National Park, Wyoming. University of Utah researchers have published 17 years worth of GPS data showing how a giant plume of hot and molten rock beneath Yellowstone shapes the landscape of the park and a wide area around it.
A 17-year University of Utah study of ground movements shows that the power of the huge volcanic hotspot beneath Yellowstone National Park is much greater than previously thought during times when the giant volcano is slumbering.
The $2.3 million study, which used Global Positioning System (GPS) satellites to measure horizontal and vertical motions of Earth’s crust from 1987 to 2004, found that the gigantic underground plume of molten rock known as the Yellowstone hotspot exerts itself forcefully even when it isn’t triggering eruptions and earthquakes:
-- As it bulges upward, the hotspot expends 10 times more energy by gradually deforming Earth’s crust at Yellowstone than by producing earthquakes.
-- The subterranean volcanic plume, 300 miles wide at its top end, may explain why ground along the Teton fault moves in directions just the opposite of those expected, a perplexing discovery that complicates efforts to predict when the fault might generate disastrous 7.5 earthquakes near the ski resorts of Jackson Hole.
-- Molten rock and hot water generated by the hotspot continue to make the 45-by-30-mile Yellowstone caldera – a giant crater – huff upward and puff downward without producing eruptions. Measurements since the newly published study ended in 2004 show the caldera rising upward at a faster rate than ever observed before.
"The Yellowstone hotspot has had a much bigger effect over a larger area with more energy than ever expected," says University of Utah geophysics Professor Robert B. Smith, who led the study, which was scheduled for publication Friday, March 2, 2007, in the Journal of Geophysical Research – Solid Earth.
"We’re seeing large-scale deformation of the Earth’s crust in the western United States because of the effects of the Yellowstone hotspot," says Christine Puskas, a University of Utah geophysics doctoral student and the study’s first author.
The study was conducted by Puskas, Smith, University of Utah postdoctoral fellow Wu-Lung Chang and former Utah researcher Chuck Meertens, now at UNAVCO, a consortium that studies deformation of Earth’s crust. Measurements also were made by the National Park Service, U.S. Geological Survey, Idaho National Laboratory, Brigham Young University, MIT and the National Geodetic Survey. Smith estimated the participants spent about $2.3 million for the 17 years of measurements.
The new study is based on measurements made from 1987 until 2004. The measurements included 17 one- to three-month-long "campaigns," during which portable GPS receivers were placed for two to 10 days each at 90 to 140 benchmarks in the Yellowstone-Teton-eastern Snake River Plain region of Wyoming, Montana and Idaho. More data came from 15 permanent GPS receiver sites installed during 1996-2003.
GPS allows precise surveying of ground movements because two dozen Navstar GPS satellites orbiting Earth broadcast time signals. GPS receivers on the ground record the signals, making it possible to triangulate each receiver’s location to within a few tenths of an inch horizontally and vertically.
Restless Volcanic Caldera Huffs and Puffs
The study summarizes the movements of the floor of the 45-by-30-mile Yellowstone caldera – a gigantic volcanic crater formed by a catastrophic eruption 642,000 years ago that spread volcanic ash over half of North America and was 1,000 times bigger than the 1980 eruption of Mount St. Helens in Washington state. Other huge Yellowstone eruptions happened 1.3 million and 2 million years ago, with 30 much smaller but still large eruptions between and since the three cataclysmic blasts.
Due to underground movement of molten rock and hot water, calderas often huff upward and puff downward for tens of thousands of years without catastrophic eruptions.
Earlier research found that a flattened chamber of partly molten rock extends from about 5 miles beneath the Yellowstone caldera down to a depth of at least 10 miles, heated by the much larger, underlying hotspot. The 50-mile-wide hotspot plume of molten rock originates at least 410 miles underground in Earth’s mantle and rises to 75 miles below the caldera, where it hits cooler rock and spreads out to a width of 300 miles.
Conventional surveying of Yellowstone began in 1923. Measurements showed the caldera floor rose 40 inches during 1923-1984, and then fell 8 inches during 1985-1995.
The GPS data show the Yellowstone caldera floor sank 4.4 inches during 1987-1995. From 1995 to 2000, the caldera rose again, but the uplift was greatest – 3 inches – at Norris Geyser Basin, just outside the caldera’s northwest rim. During 2000-2003, the northwest area rose another 1.4 inches, but the caldera floor itself sank about 1.1 inches.
Smith and Puskas believe the caldera sank when hot water, steam and gases migrated northwest out of the caldera and to the Norris area, making that area rise.
While not part of the new published study, Smith reported at an American Geophysical Union meeting last December that 2004-2006 GPS measurements show the northwest caldera area sank by 3.2 inches, but the central caldera floor rose faster than ever recorded: about 6.7 inches since mid-2004.
"The rate is unprecedented, at least in terms of what scientists have been able to observe in Yellowstone," Smith says. "We think it’s a combination of magma [molten rock] being intruded under the caldera and hot water released from the magma being pressurized because it’s trapped. I don’t believe this is evidence for an impending volcanic eruption. But it would be prudent to keep monitoring the volcano."
Puskas adds: "This episode may represent a period like those observed at other large volcanic systems such as Long Valley caldera, California, where episodes of unrest have lasted one to four years, with uplift rates as high as 4 inches a year."
The fact some GPS receivers now are permanently installed in Yellowstone and provide data daily made researchers realize that ups-and-downs of the caldera occur not just in decades or years, but in months, reflecting underground movements of molten rock and hot water that "also happen over months," Puskas says.
Hotspot’s Bulge May Explain a New Mystery on the Teton Fault
The Yellowstone hotspot made overlying region bulge upward by one-third mile during the past 2 million years, lifting the Yellowstone Plateau to 8,000 feet elevation.
Smith and Puskas say 1987-2004 GPS measurements show the southwest part of the Yellowstone Plateau is slowly sliding downhill to the southwest at about one-sixth inch per year. That may explain the study’s biggest surprise: ground along the Teton fault moves opposite the expected direction.
The fault runs 40 miles north-south along the eastern base of the Teton Range. It is a "normal" fault, which means that during large quakes, the mountains rise upward and move westward, while the valley of Jackson Hole – just east of the mountains – drops downward and moves eastward. That is because the Teton region is part of the Basin and Range Province of the West, where Earth’s crust is pulled apart east-west between the Sierra Nevada in California and the Rocky Mountains in Utah, Wyoming and Montana.
The vertical movement totals about 3 to 6 feet during a single magnitude-7 quake. Previous evidence indicates there were thousands of magnitude-7 to 7.5 quakes during the past 13 million years, lifting the tallest Teton peaks to altitudes of more than 13,000 feet – almost 7,000 feet above Jackson Hole. Such a quake today would be a major disaster for Jackson, Wyo., and nearby towns.
Yet 17 years of GPS measurements show "the textbook model for a normal fault is not what’s happening at the Teton fault," Smith says. "The mountains are going down relative to the valley going up. That’s a total surprise."
The results – Jackson Hole moved west one-quarter inch and upward 1.7 inches from 1987 to 2004 – mean the Teton Range and Jackson Hole valley are being squeezed together rather than stretched apart, as was expected.
Smith believes the bulging Yellowstone hotspot, located north of the Tetons, may be "pushing Jackson Hole into the Teton Range." This unexpected pressure may explain why there have been no magnitude-7 quakes on the fault since the last one about 4,800 years ago, yet also may allow pressure to build for the next disastrous quake.
"The question is how do you store the stress that is leading to the next big earthquake?" Smith says. "It might include episodes of compression and stretching, and eventually the dominant Basin and Range stretching prevails" to trigger a big quake.
Slow Deformation Overpowers Quick Earthquakes
During the new study, Puskas converted GPS-measured ground movements and records of historic earthquake magnitudes into a quantity known as a "moment," which measures the energy expended to deform the landscape. That allowed her to compare total ground deformation measured by GPS with ground deformation caused by quakes.
She found the ground-moving energy of Yellowstone’s frequent, mostly small quakes was overpowered 10-to-1 by the energy generated from other ground-moving forces. Those include the Yellowstone hotspot’s bulging uplift of the landscape, smaller volcanic ups and downs within the caldera, relaxation of the ground after quakes, and Basin-and-Range stretching of Earth’s crust that ultimately will generate future quakes.
Smith says the fact non-seismic forces to overwhelm quake energies by 10-to-1 "means there is much more energy related to active volcanic processes of uplift and extension of the Earth’s surface," he says.
An example: The southwestern Yellowstone Plateau is moving southwest at one-sixth inch per year, twice as fast as the next block of land to the southwest: the eastern Snake River Plain. Land from Island Park, Idaho, southwest to Idaho Falls is being squeezed by the collision. Smith says that represents a lot of energy in a small area because the entire 600-mile-wide Basin and Range Province between the Sierra and the Rockies is stretching apart only three times faster, or about a half inch per year.
Source: University of Utah
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Post by Watchman on Nov 9, 2007 13:16:12 GMT -5
Ground Is Rising at Yellowstone Park
WASHINGTON (AP) - Yellowstone National Park, once the site of a giant volcano, has begun swelling up, possibly because molten rock is accumulating beneath the surface, scientists report.
But, "there is no evidence of an imminent volcanic eruption," said Robert B. Smith, a professor of geophysics at the University of Utah.
Many giant volcanic craters around the world go up and down over decades without erupting, he said.
Smith and colleagues report in Friday's issue of the journal Science that the flow of the ancient Yellowstone crater has been moving upward almost 3 inches per year for the past three years.
That is more than three times faster than ever observed since such measurements began in 1923, the researchers said.
"Our best evidence is that the crustal magma chamber is filling with molten rock," Smith said in a statement. "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."
It's not unusual for ancient volcano sites like Yellowstone and Long Valley, Calif., to rise and fall, according to the researchers.
The Yellowstone volcanic field was produced by what the researchers described as a plume of hot and molten rock beginning at least 400 miles beneath Earth's surface and rising to 30 miles underground, where it widens to about 300 miles across.
Blobs of molten rock sometimes rise to refill the magma chamber beneath Yellowstone.
The volcano at Yellowstone produced massive eruptions 2 million, 1.3 million and 642,000 years ago, all larger than the 1980 eruption of Mount St. Helens.
Site of the famed Old Faithful and hundreds of other geysers, Yellowstone sprawls across parts of Wyoming, Montana and Idaho.
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Post by Watchman on Nov 14, 2007 13:01:07 GMT -5
Yellowstone: the time bomb under America
Deep beneath Yellowstone National Park lies a vast super-volcano which, if it blew up, could devastate much of the US. Recently, it's been a bit too restless for comfort. David Usborne reports Published: 10 November 2007
Visitors to Yellowstone National Park in the north-western United States know not to be careless about the bears that roam its pines or the many hissing and sizzling geysers that dot its magnificent landscape. Few ever worry about being blown into space, though.
Startling new geological data published yesterday in the journal Science suggests that it might be a good idea for most of us – and certainly those living in the region – to be aware that there is more to Yellowstone than grand vistas and abundant wildlife. The hot springs are a clue to what lies beneath: seething layers of molten magma, super-heated gases and hydrothermal liquids.
Yellowstone straddles one of Earth's most studied "hot-spots", where fissures in the crust, created by volcanic eruptions of eons past, have allowed giant streams of molten rock, or magma, to push closer than normal to the planet's surface. In recent years something intriguing – if not to say thoroughly nerve-rattling – has been going on. The magma is on the move. And so is Yellowstone.
Over the past three years, according to the report, the ground in the volcanic caldera that spans about 925 square miles and accounts for much of the park's terrain has been rising towards the sky at the rate of almost three inches per year. That is three times faster than has ever been observed before. It raises the obvious question: what is happening under the park? And what might be about to happen?
The study's authors are aware, of course, that the notion of Yellowstone being some kind of humming volcanic time-bomb is not something that tourism officials will want to advertise. And, indeed, any kind of panic because of the new data, remarkable though it is, would be entirely misplaced, they insist. "There is no evidence of an imminent volcanic eruption or hydrothermal explosion. That's the bottom line," insists Robert Smith, a professor of geophysics at the University of Utah and the lead researcher in this study. "A lot of calderas worldwide go up and down over decades without erupting."
It may also be reassuring to know that no very big bangs have happened at Yellowstone for a very long time. The caldera, the walls of which are easily discernible from some vantage points in the park, was formed by some massive eruption past when a more classic-looking volcanic cone was probably obliterated. And while the park is still technically a "super-volcano" , it is estimated that it has not blown its top for 640,000 years. If you are planning to be in the park on a Thursday next March, therefore, the chances of it detonating that particular afternoon are surely slim.
No one is about to take their eyes off the park, however, not least because of these unusual new findings that suggest at least that pressures beneath the ground are rising. Moreover, geologists are well aware that were a major eruption indeed to happen, the impact would rival any natural disaster the world has ever seen. Remember the destruction when Mount St Helens flipped her lid in 1980, turning 240 square miles into a wasteland? The energy released at Yellowstone would be many hundreds of times greater.
Moreover, Yellowstone may be due a massive release. Geologists believe that the super-volcano beneath the park has undergone major eruptions at roughly 650,000-year intervals. There have been about 140 such events over 16 million years. Because the last serious explosion is believed to have taken place 640,000 years ago – although there was a minor flare-up 70,000 years ago – who is to say, really, that another one is indeed not imminent? Scientists have been observing the rising and falling of the ground at Yellowstone since 1923. The last most rapid period of upward movement occurred between 1976 and 1985, but only at a rate of about one inch a year. Professor Smith and his assistants began taking their readings in 2004 with instruments aided by satellite tracking placed at numerous spots across the caldera. They have even observed undulations in the caldera's surface, with some spots rising faster than others one year and then slowing down again while different areas catch up.
In the study, Accelerated Uplift and Magmatic Intrusion of the Yellowstone Caldera, 2004 to 2006, the authors note that while most of the magma remains about 400 miles below the surface, a significant plume rises to about 30 miles deep, where it spreads out horizontally like a pancake that is larger than Los Angeles. It seems likely that the pancake is expanding and causing the floor of the caldera suddenly to rise.
"Our best evidence is that the crustal magma chamber is filling with molten rock," Professor Smith explained. "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." In other words, something is afoot, but no techniques exist to forecast what comes next. The prediction is easier for single-channel, cone volcanoes. At a caldera such as Yellowstone, the magma could suddenly blow through at any number of locations. "We use the term 'restless' to describe these systems," Professor Smith said.
And what if the ground at Yellowstone does not start to go down? Well, these calderas, he admits, "occasionally they burp". Let's hope the park's belly-ache resolves itself – such a "burp" would shake half of the planet.
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