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  • richardmitnick 2:51 pm on April 21, 2018 Permalink | Reply
    Tags: , U Oregon, Yellowstone Caldera, Yellowstone National Park   

    From U Oregon and Science Alert: Yellowstone and its environs” 

    University or Orgeon

    Science Alert

    1
    (Jonathan Newton/The Washington Post) & Science Alert

    Yellowstone National Park sits squarely over a giant, active volcano. This requires attention.

    Yellowstone has been a national park since 1872, but it was only in the 1960s that scientists realized the scale of the volcano — it’s 44 miles across — and not until the 1980s did they grasp that this thing is fully alive and still threatens to erupt catastrophically.

    Yellowstone is capable of eruptions thousands of times more violent than the Mount St. Helens eruption of 1980. The northern Rockies would be buried in multiple feet of ash. Ash would rain on almost everyone in the United States. It’d be a bad day. Thus geologists are eager to understand what, exactly, is happening below all those volcano-fueled hot springs and geysers.

    Obviously they would like to know if and when Yellowstone will blow again, and with what level of explosiveness. A major eruption would be a low-probability, high-consequence event, a proverbial Black Swan, something that could have societal and planetary effects. The problem for scientists is that these big “supervolcano” eruptions rarely happen, and the most important action is out of sight, many miles below the surface, involving chaotic forces, complex chemistry and enigmatic geological features.

    One new study has offered insight on Yellowstone’s hidden architecture. It modeled the way magma rises from deep in Earth’s interior and creates two large chambers of partially melted rock beneath the surface of the national park.

    These two magma chambers are stacked, and they are separated by a layer (called a “sill,” like a window sill) of non-melted rock. The magma rising from Earth’s mantle flows easily and doesn’t hold much gas. It cools and solidifies as it collides with relatively cold crust, forming the sill, the top of which is about six miles below the surface.

    On top of the sill is the upper magma chamber, with thick, sticky magma that holds a great deal of gas — which makes the magma in the upper chamber explosive. It’s like an unopened can of soda that has been shaken.

    5

    Open the can at your peril.

    The new study, published in Geophysical Research Letters, explains how this two-tiered, geochemically diverse architecture might have come about over the course of time.

    “Someday we might have a model snapshot saying this is what the system looks like when there’s enough melt for there to be a large eruption,” lead author Dylan Colón, an earth sciences doctoral candidate at the University of Oregon, told The Washington Post.

    The study won praise from Michael Poland, scientist-in-charge at the U.S. Geological Survey’s Yellowstone Volcano Observatory: “What’s neat about their model is they can go back in time with it and see how it might have influenced eruption rates many millions of years ago.”

    The new study bolsters earlier research on the dual magma chambers.

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    Image credit: NPS

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    (Hsin-Hua Huang/University of Utah)

    It used sensors arrayed around Yellowstone to record the speed at which seismic waves from small earthquakes pass through the subsurface rock. Such waves move more slowly through hot and/or partially melted rock formations. That data gave scientists the equivalent of an MRI showing the two magma chambers.

    “Supervolcano,” we should note, is not a technical term. The experts refer to Yellowstone as a “caldera” or a “caldera-forming volcano.” Some volcanoes form conical mountains. A caldera is a volcano that creates a vast crater. These are mountain-swallowing events. Visitors to Yellowstone are given a map showing the outline of the most recent caldera, and if they go to the right vantage point, it’s possible to see that the heart of the park is remarkably free of mountains. They were either blown away or fell into the big hole.

    The Yellowstone region has seen three big eruptions, the first one 2.1 million years ago, the most recent 630,000 years ago. Contrary to Internet rumor-mongering, as well as conspiracy theories about government coverups, there’s no sign that a fourth cataclysmic event is about to happen.

    It’s possible, in fact, that Yellowstone is getting a bit old and tired. It may be ready for a long nap rather than a major eruption.

    Ilya Bindeman, a University of Oregon geochemist and co-author of the new paper, said that Yellowstone may be “approaching the end of its evolution” because so much of the material in the upper magma chamber is recycled and re-melted after previous eruptions.

    As Poland said: “How many times do you want to reheat your leftovers? At some point you’re going to say, ‘I’m not going to reheat his.’ You’ve microwaved it six times, and it’s no longer food.”

    Intellectual humility is called for here: No one can say with great confidence how much magma it takes to trigger a caldera-forming eruption. Moreover, relatively small eruptions creating lava flows can happen within the Yellowstone system. The most recent was 70,000 years ago. The experts say one of these smaller eruptions is much more likely than a giant explosion. Speculation that Yellowstone is “due” to erupt catastrophically implies that the volcano behaves predictably, like a machine. Geologists know otherwise.

    Yellowstone, it should be noted, isn’t the only caldera in the United States. One of the others that’s worth keeping an eye on — and the U.S. Geological Survey does just that — is the Long Valley caldera in California, near the popular ski resort of Mammoth Mountain, just east of Yosemite National Park. It erupted 700,000 years ago. A major eruption is extremely unlikely, but it could produce smaller eruptions that would be highly disruptive and dangerous, said Margaret Mangan, scientist-in-charge at the USGS California Volcano Observatory.

    Mangan said there are seven volcanic regions in California with zones of molten rock beneath the surface. A volcanic eruption in California is roughly as likely as a magnitude 6 or greater earthquake on the San Andreas Fault, she said.

    But Californians don’t worry about volcanoes. They worry about earthquakes, tsunamis and wildfires, she said. She has tried to raise public awareness of volcano hazards but says that it is hard to get much attention.

    “The awareness level and preparedness level is quite low in this state,” she said. “We prepare for those large earthquake events, and we need to prepare for volcanic eruptions.”

    See the full article here .

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    The University of Oregon (also referred to as UO, U of O or Oregon) is a public flagship research university in Eugene, Oregon. Founded in 1876, the institution’s 295-acre campus is along the Willamette River. Since July 2014, UO has been governed by the Board of Trustees of the University of Oregon. The university has a Carnegie Classification of “highest research activity” and has 19 research centers and institutes. UO was admitted to the Association of American Universities in 1969.

    The University of Oregon is organized into five colleges (Arts and Sciences, Business, Design, Education, and Honors) and seven professional schools (Accounting, Architecture and Environment, Art and Design, Journalism and Communication, Law, Music and Dance, and Planning, Public Policy and Management) and a graduate school. Furthermore, UO offers 316 undergraduate and graduate degree programs. Most academic programs follow the 10 week Quarter System.

    UO student-athletes compete as the Ducks and are part of the Pac-12 Conference in the National Collegiate Athletic Association (NCAA). With eighteen varsity teams, the Oregon Ducks are best known for their football team and track and field program.

     
  • richardmitnick 9:17 am on January 3, 2018 Permalink | Reply
    Tags: , , , Yellowstone Caldera   

    From ScienceNews: “A sinking, melting ancient tectonic plate may fuel Yellowstone’s supervolcano” 

    ScienceNews bloc

    ScienceNews

    January 2, 2018
    Carolyn Gramling

    Computer simulations suggest that a core-deep plume of magma isn’t needed to power the massive eruptions.

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    HOT SPOT The Yellowstone supervolcano has a 17-million-year history of eruptions in the western United States. Now scientists say the source of the supervolcano’s heat isn’t a deep mantle plume, but the downward drag of an ancient subducting slab stirring up the mantle. Riishede/iStockphoto.

    Computer simulations show that movement of broken-up remnants of the ancient Farallon Plate could be stirring the mantle in a way that fuels Yellowstone, researchers report December 18 in Nature Geoscience. “The fit is so good,” says study coauthor Lijun Liu, a geodynamicist at the University of Illinois at Urbana-Champaign.

    The giant supervolcano now beneath Yellowstone National Park, located mostly in Wyoming, has a 17-million-year history — much of it on the move. In that time, the locus of volcanism has moved northeastward from southwestern Idaho to its current location, where it most recently explosively erupted about 640,000 years ago. These shifting eruptions have created a track of volcanic craters resembling those created by the hot spot that formed the Hawaiian island chain. As a result, scientists have long suspected that a deep plume of magma originating from the core-mantle boundary, similar to the one that fuels Hawaii’s volcanoes, is the source of Yellowstone’s fury.

    But the nature of the Yellowstone plume has been the subject of debate. “Usually with plumes, we can trace them to the core-mantle boundary,” says Robert Porritt, a seismologist at the University of Texas at Austin, who was not involved in the new work. To “see” Earth’s structure, seismologists use a technique called seismic tomography, which maps the interior using seismic waves generated by earthquakes. Particularly hot or liquid parts of the mantle slow some seismic waves known as shear waves. Tomographic images of mantle plumes such as the one beneath Hawaii show a low-velocity region that extends all the way down to the boundary between mantle and core, about 2,900 kilometers below Earth’s surface. Such deep plumes are thought to be necessary to provide sufficient heat for the volcanism.

    “But at Yellowstone, we don’t have that large low-shear velocity thing at the core-mantle boundary,” Porritt says. Current images suggest a region of low-velocity material extending at least 1,000 kilometers deep — but whether there is a deeper plume is uncertain.

    And the region is tectonically complex. About 200 million years ago, a tectonic plate to the west, known as the Farallon Plate, began to slide eastward beneath the North American Plate. The current Juan de Fuca Plate off the Pacific Northwest coast, one of the last remnants of the Farallon Plate, continues to slide beneath the western United States. Some researchers have suggested that, instead of a deep mantle plume, the flexing and melting of the subducting Juan de Fuca Plate are responsible for Yellowstone’s volcanism.

    ______________________________________________________________________
    Dragging down

    The Farallon Plate began subducting eastward beneath the North American Plate hundreds of millions of years ago. The youngest part of the slab, called the Juan de Fuca Plate (green), now partly lies beneath the western United States. In a new study, simulations suggest that the downward pull of the ancient Farallon Plate (blue) is driving the flow of hot mantle from west to east. As that hot mantle (dark orange) rises through breaks in the Juan de Fuca Plate, some of mantle circulates westward, fueling volcanism in the Basin and Range region. And some flows to the east, fueling Yellowstone.

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    Q. Zhou, L. Liu and J. Hu/Nature Geoscience 2017
    ______________________________________________________________________

    Liu and his colleagues have yet another idea. In 2016, Liu published research suggesting that the sinking ancient Farallon slab was acting like a lid on a deep mantle plume, preventing the plume from rising to the surface (SN Online: 2/3/16). “But we kept in mind that the problem was not solved,” Liu says. “The heat source [for Yellowstone] was still missing.”

    The researchers created a sophisticated, supercomputer-driven series of simulations to try to find the best scenario that matches the three known knowns: the current tomographic images of the subsurface beneath the western United States; the volcanic history at Yellowstone as well as in the nearby Basin and Range regions; and the movements of the subducting slab since about 20 million years ago.

    Yellowstone’s volcanism is linked not just to the currently subducting young Juan de Fuca Plate, but also to the remnants of its older incarnation, the Farallon Plate, the simulations suggest. Those remnants have continued to slide deeper and now lie beneath the eastern United States. This downward dive dragged hot mantle eastward along with it. As the Juan de Fuca Plate began to break up beneath the western United States, the hot mantle rose through the cracks. Some of that hot mantle circulated back to the west across the top of the Juan de Fuca Plate, fueling volcanism in the Basin and Range region. And some of it flowed eastward, adding heat to Yellowstone’s fire. The study doesn’t rule out the presence of a deep magma plume, but it suggests that such a plume plays little role in Yellowstone’s volcanism.

    Porritt says he’s intrigued by the idea that the sinking Farallon slab beneath the central and eastern United States could be driving mantle circulation on such a large scale. However, he says, he isn’t convinced that the authors have truly solved the larger mystery of Yellowstone’s volcanism — or that a yet-to-be-found deep plume still isn’t playing a major role. “It’s an interesting debate that’s going to be raging, hopefully for decades.”

    See the full article here .

    Science News is edited for an educated readership of professionals, scientists and other science enthusiasts. Written by a staff of experienced science journalists, it treats science as news, reporting accurately and placing findings in perspective. Science News and its writers have won many awards for their work; here’s a list of many of them.

    Published since 1922, the biweekly print publication reaches about 90,000 dedicated subscribers and is available via the Science News app on Android, Apple and Kindle Fire devices. Updated continuously online, the Science News website attracted over 12 million unique online viewers in 2016.

    Science News is published by the Society for Science & the Public, a nonprofit 501(c) (3) organization dedicated to the public engagement in scientific research and education.

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  • richardmitnick 8:27 am on October 30, 2017 Permalink | Reply
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    From Science: “Yellowstone’s massive volcano could erupt more frequently than scientists thought” 

    ScienceMag
    Science Magazine

    Oct. 25, 2017
    Paul Voosen

    1
    iStock.com/kwiktor

    Some 630,000 years ago, the supervolcano beneath Yellowstone National Park in Wyoming recorded its last catastrophic eruption, forming a caldera that nearly spans the park’s width and belching a thick layer of ash, or tephra, across North America. But rather than a single event, Yellowstone may have erupted twice in a span of 270 years, new evidence from mud cores discovered off the coast of Santa Barbara, California, indicates. The cores, presented here today at the annual meeting of the Geological Society of America, were captured at the farthest extent of the ash’s reach, recorded as wisps of tephra in finely sedimented, ancient mud uplifted near the ocean floor. Most evidence of the Yellowstone eruption (the park’s Grand Prismatic geyser is pictured) is found on land in thick layers of compacted, weathered rock, which could have easily hidden the dual eruption, the researchers say. Both tephra layers also coincide with a stark temperature decline of 3°C, according to the core’s records of oxygen isotopes and fossilized plankton, with each episode lasting 100 years or more. If confirmed, the research could indicate that Yellowstone can recharge its eruptions much more quickly than typically thought—and that traditional views of volcanic winter, the period of cooling caused by a volcano’s reflective droplets and ash, fail to explain how a century of cooling could follow the eruptions.

    See the full article here .

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  • richardmitnick 11:36 am on October 18, 2017 Permalink | Reply
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    From NYT: “A Surprise From the Supervolcano Under Yellowstone” 

    New York Times

    The New York Times

    OCT. 10, 2017
    SHANNON HALL

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    The Grand Prismatic Spring in Yellowstone National Park, a large hot spring known for its vibrant coloration. Beneath the park is a powerful supervolcano which drives the spring and other geological activity. Credit Marie-Louise Mandl/EyeEm, via Getty Images.

    Beneath Yellowstone National Park lies a supervolcano, a behemoth far more powerful than your average volcano. It has the ability to expel more than 1,000 cubic kilometers of rock and ash at once — 2,500 times more material than erupted from Mount St. Helens in 1980, which killed 57 people. That could blanket most of the United States in a thick layer of ash and even plunge the Earth into a volcanic winter.

    Yellowstone’s last supereruption occurred 631,000 years ago. And it’s not the planet’s only buried supervolcano. Scientists suspect that a supereruption scars the planet every 100,000 years, causing many to ask when we can next expect such an explosive planet-changing event.

    To answer that question, scientists are seeking lessons from Yellowstone’s past. And the results have been surprising. They show that the forces that drive these rare and violent events can move much more rapidly than volcanologists previously anticipated.

    The early evidence, presented at a recent volcanology conference, shows that Yellowstone’s most recent supereruption was sparked when new magma moved into the system only decades before the eruption. Previous estimates assumed that the geological process that led to the event took millenniums to occur.

    To reach that conclusion, Hannah Shamloo, a graduate student at Arizona State University, and her colleagues spent weeks at Yellowstone’s Lava Creek Tuff — a fossilized ash deposit from its last supereruption. There, they hauled rocks under the heat of the sun to gather samples, occasionally suspending their work when a bison or a bear roamed nearby.

    Ms. Shamloo later analyzed trace crystals in the volcanic leftovers, allowing her to pin down changes before the supervolcano’s eruption. Each crystal once resided within the vast, seething ocean of magma deep underground. As the crystals grew outward, layer upon layer, they recorded changes in temperature, pressure and water content beneath the volcano, much like a set of tree rings.

    “We expected that there might be processes happening over thousands of years preceding the eruption,” said Christy Till, a geologist at Arizona State, and Ms. Shamloo’s dissertation adviser. Instead, the outer rims of the crystals revealed a clear uptick in temperature and a change in composition that occurred on a rapid time scale. That could mean the supereruption transpired only decades after an injection of fresh magma beneath the volcano.

    The time scale is the blink of an eye, geologically speaking. It’s even shorter than a previous study that found that another ancient supervolcano beneath California’s Long Valley caldera awoke hundreds of years before its eruption. As such, scientists are just now starting to realize that the conditions that lead to supereruptions might emerge within a human lifetime.

    “It’s shocking how little time is required to take a volcanic system from being quiet and sitting there to the edge of an eruption,” said Ms. Shamloo, though she warned that there’s more work to do before scientists can verify a precise time scale.

    Kari Cooper, a geochemist at the University of California, Davis who was not involved in the research, said Ms. Shamloo and Dr. Till’s research offered more insights into the time frames of supereruptions, although she is not yet convinced that scientists can pin down the precise trigger of the last Yellowstone event. Geologists must now figure out what kick-starts the rapid movements leading up to supereruptions.

    “It’s one thing to think about this slow gradual buildup — it’s another thing to think about how you mobilize 1,000 cubic kilometers of magma in a decade,” she said.

    As the research advances, scientists hope they will be able to spot future supereruptions in the making. The odds of Yellowstone, or any other supervolcano, erupting anytime soon are small. But understanding the largest eruptions can only help scientists better understand, and therefore forecast, the entire spectrum of volcanic eruptions — something that Dr. Cooper thinks will be possible in a matter of decades.

    See the full article here .

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  • richardmitnick 12:29 pm on November 21, 2016 Permalink | Reply
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    From Science Alert: “We’re about to find out what’s rumbling below the Yellowstone Supervolcano” 

    ScienceAlert

    Science Alert

    16 NOV 2016
    BEC CREW

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    Grand Prismatic Spring, Yellowstone. Credit: Filip Fuxa/Shutterstock.com

    And what makes it so damn explosive.

    For the first time, scientists have started to map what lurks beneath the Yellowstone Supervolcano in Wyoming, so we can finally see the vast subterranean systems that fuel the famous Old Faithful geyser, and other hydrothermal vents at Yellowstone National Park.

    These maps will also allow us to better predict if and when a ‘super-eruption’ could occur in the area – something that hasn’t happened in 13,800 years, but when it did, it left behind the largest crater of its kind on the planet.

    “This is really kind of a last frontier if you will, in Yellowstone, of being able to look at a large part that’s underground that people have not looked at,” one of the team Carol Finn, from the US Geological Survey, told the media.

    “There’s just a lot we don’t know, and this survey is really exciting because it’s going to be the first view of a large portion of the groundwater system, of the water underground that feeds all of these thermal features.”

    You might imagine the Yellowstone Supervolcano as like a supersized volcano, rising up out of the ground and puffing whirls of menacing smoke from its gaping mouth, but in reality, it’s like a giant volcano that collapsed in on itself to form vast cauldron-like depressions.

    These depressions are called caldera, and they form when a volcano spews so much magma during an eruption, its now-empty chamber causes the whole thing to collapse like a massive sinkhole, leaving behind a massive crater.

    But it’s not like these craters have stopped exploding – the entire Yellowstone Supervolcano is like a vast volcanic field, covering an area of roughly 55 by 72 km (34 by 45 miles), where lava eruptions and swelling steam vents litter the otherworldly landscape.

    There have been three super-eruptions over the past couple of million years, with the Huckleberry Ridge eruption 2.1 million years ago; the Mesa Falls eruption 1.3 million years ago; and the Lava Creek eruption roughly 630,000 years ago.

    A smaller steam explosion around 13,800 years ago left behind a 5-km-diameter (3.1-mile) crater on the edge of Yellowstone Lake, which is thought to be the largest of its kind in the world.

    According to the Yellowstone National Park, 20 visitors have died due to minor explosions from the geothermal vents and hot spring – the most recent in 2000, when a tourist was scalded by boiling waters as hot as 121 degrees Celsius (250 degrees Fahrenheit).

    Needless to say, this is not a place that we want to be surprised by. It’s time we knew exactly what’s lurking below, so we can do a better job at predicting these explosions – large, small, and super.

    The new mapping project, which got underway on November 7, is starting with a helicopter electromagnetic and magnetic survey, which can sense even the tiniest voltages sparking underground.

    The helicopter is fitted with a giant, hoop-shaped electromagnetic system, which it suspends over the Yellowstone grounds by flying around 60 metres (200 feet) above the surface.

    Not only can this equipment detect subterranean electrical activity from above the surface, it also acts like a giant X-ray machine, detecting the shapes and behaviour of things like geysers, hot springs, mud pots, steam vents, and hydrothermal explosion craters to depths of up to 500 metres (1,500 feet).

    It will also be able to detect where and how hot water flows beneath the surface.

    “Nobody knows anything about the flow paths” of hot water that erupts from Yellowstone’s geysers, Finn told the Associated Press. “Does it travel down and back up? Does it travel laterally?”

    What we do know, thanks to study carried out last year, is that there’s way more magma below Yellowstone than anyone had imagined, with researchers detecting a second reservoir of hot, partly molten rock underneath the more shallow magma chamber we already knew about.

    As we reported back in April 2015, this vast reservoir lies some 20-45 kilometres (12-27 miles) beneath the supervolcano, and this new chamber could fill the Grand Canyon up 11.2 times.

    And we don’t want any of that fuelling a calderic eruption without some kind of warning first, as Sarah Kaplan reports for The Washington Post:

    “A calderic eruption, in which that magma came rushing to the surface, would eject 1,000 times more material than the 1980 eruption of Mount St. Helens [the deadliest eruption in US history], and could create a caldera dozens of miles wide.

    The last time this happened, 640,000 years ago, Homo sapiens didn’t even exist yet. No one is certain what causes such an eruption, or when the Yellowstone supervolcano might erupt again.”

    The mapping survey is being run by the US Geological Survey, the University of Wyoming, and the Aarhus University in Denmark. It’s expected to take four weeks, and it will inform future ground-based surveys around the volcanic hotspot.

    We seriously cannot wait to see what they find.

    See the full article here .

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  • richardmitnick 8:39 pm on May 15, 2016 Permalink | Reply
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    From livescience: “What Would Happen If Yellowstone’s Supervolcano Erupted?” 

    Livescience

    May 2, 2016
    Becky Oskin

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    Hot springs in Yellowstone National Park are just one of the types of thermal features that result from volcanic activity. Credit: Dolce Vita / Shutterstock.com

    Although fears of a Yellowstone volcanic blast go viral every few years, there are better things to worry about than a catastrophic supereruption exploding from the bowels of Yellowstone National Park.

    Caldera at Yellowstone  Image not credited
    Caldera at Yellowstone Image not credited

    Scientists at the U.S. Geological Survey’s (USGS) Yellowstone Volcano Observatory always pooh-pooh these worrisome memes, but that doesn’t mean researchers are ignoring the possible consequences of a supereruption. Along with forecasting the damage, scientists constantly monitor the region for signs of molten rock tunneling underground. Scientists scrutinize past supereruptions, as well as smaller volcanic blasts, to predict what would happen if the Yellowstone Volcano did blow. Here’s a deeper look at whether Yellowstone’s volcano would fire up a global catastrophe.

    Probing Yellowstone’s past Most of Yellowstone National Park sits inside three overlapping calderas. The shallow, bowl-shaped depressions formed when an underground magma chamber erupted at Yellowstone. Each time, so much material spewed out that the ground collapsed downward, creating a caldera. The massive blasts struck 2.1 million, 1.3 million and 640,000 years ago. These past eruptions serve as clues to understanding what would happen if there was another Yellowstone megaexplosion.

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    An example of the possible ashfall from a month-long Yellowstone supereruption. Credit: USGS –

    If a future supereruption resembles its predecessors, then flowing lava won’t be much of a threat. The older Yellowstone lava flows never traveled much farther than the park boundaries, according to the USGS. For volcanologists, the biggest worry is wind-flung ash. Imagine a circle about 500 miles (800 kilometers) across surrounding Yellowstone; studies suggest the region inside this circle might see more than 4 inches (10 centimeters) of ash on the ground, scientists reported* Aug. 27, 2014, in the journal Geochemistry, Geophysics, Geosystems.

    The ash would be pretty devastating for the United States, scientists predict. The fallout would include short-term destruction of Midwest agriculture, and rivers and streams would be clogged by gray muck. People living in the Pacific Northwest might also be choking on Yellowstone’s fallout. “People who live upwind from eruptions need to be concerned about the big ones,” said Larry Mastin, a USGS volcanologist and lead author of the 2014 ash study. Big eruptions often spawn giant umbrella clouds that push ash upwind across half the continent, Mastin said. These clouds get their name because the broad, flat cloud hovering over the volcano resembles an umbrella. “An umbrella cloud fundamentally changes how ash is distributed,” Mastin said. But California and Florida, which grow most of the country’s fruits and vegetables, would see only a dusting of ash. A smelly climate shift.

    Yellowstone Volcano’s next supereruption is likely to spew vast quantities of gases such as sulfur dioxide, which forms a sulfur aerosol that absorbs sunlight and reflects some of it back to space. The resulting climate cooling could last up to a decade. The temporary climate shift could alter rainfall patterns, and, along with severe frosts, cause widespread crop losses and famine.

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    The walls of the Grand Canyon of Yellowstone are made up predominantly of lava and rocks from a supereruption some 500,000 years ago. Credit: USGS

    But a Yellowstone megablast would not wipe out life on Earth. There were no extinctions after its last three enormous eruptions, nor have other supereruptions triggered extinctions in the last few million years.

    “Are we all going to die if Yellowstone erupts? Almost certainly the answer is no,” said Jamie Farrell, a Yellowstone expert and assistant research professor at the University of Utah. “There have been quite a few supereruptions in the past couple million years, and we’re still around.” However, scientists agree there is still much to learn about the global effects of supereruptions. The problem is that these massive outbursts are rare, striking somewhere on Earth only once or twice every million years, one study found. “We know from the geologic evidence that these were huge eruptions, but most of them occurred long enough in the past that we don’t have much detail on what their consequences were,” Mastin said. “These events have been so infrequent that our advice has been not to worry about it.” A far more likely damage scenario comes from the less predictable hazards — large earthquakes and hydrothermal blasts in the areas where tourists roam. “These pose a huge hazard and could have a huge impact on people,” Farrell said.

    Supereruption reports are exaggerated

    Human civilization will surely survive a supereruption, so let’s bust another myth. There is no pool of molten rock churning beneath Yellowstone’s iconic geysers and mud pots. The Earth’s crust and mantle beneath Yellowstone are indeed hot, but they are mostly solid, with small pockets of molten rock scattered throughout, like water inside a sponge. About 9 percent of the hot blob is molten, and the rest is solid, scientists reported on May 15, 2015, in the journal Science. This magma chamber rests between 3 to 6 miles (5 to 10 km) beneath the park. Estimates vary, but a magma chamber may need to reach about 50 percent melt before molten rock collects and forces its way out. “It doesn’t look like at this point that the [Yellowstone] magma reservoir is ready for an eruption,” said Farrell, co-author of the 2015 study in the journal Science.

    How do researchers measure the magma? Seismic waves travel more slowly through hot or partially molten rock than they do through normal rock, so scientists can see where the magma is stored, and how much is there, by mapping out where seismic waves travel more slowly, Farrell said.

    The magma storage region is not growing in size, either, at least for as long as scientists have monitored the park’s underground. “It’s always been this size, it’s just we’re getting better at seeing it,” Farrell said.

    Watch out for little eruptions

    As with magma mapping, the science of forecasting volcanic eruptions is always improving. Most scientists think that magma buildup would be detectable for weeks, maybe years, preceding a major Yellowstone eruption. Warning signs would include distinctive earthquake swarms, gas emissions and rapid ground deformation.

    Someone who knows about these warning signals might look at the park today and think, “Whoa, something weird is going on!” Yellowstone is a living volcano, and there are always small earthquakes causing tremors, and gas seeping from the ground. The volcano even breathes — the ground surface swells and sinks as gases and fluids move around the volcanic “plumbing” system beneath the park.

    But the day-to-day shaking in the park does not portend doom. The Yellowstone Volcano Observatory has never seen warning signs of an impending eruption at the park, according to the USGS.

    What are scientists looking for? For one, the distinctive earthquakes triggered by moving molten rock. Magma tunneling underground sets off seismic signals that are different from those generated by slipping fault lines. “We would see earthquakes moving in a pattern and getting shallower and shallower,” Farrell said. To learn about the earthquake patterns to look for, revisit the 2014 eruption of Bardarbunga Volcano in Iceland. Both amateurs and experts “watched” Bardarbunga’s magma rise underground by tracking earthquakes. The eventual surface breakthrough was almost immediately announced on Twitter and other social media. As with Iceland, all of Yellowstone’s seismic data is publicly available through the U.S. Geological Survey’s Yellowstone Volcano Observatory and the University of Utah.

    “We would have a good idea that magma is moving up into the shallow depths,” Farrell said.

    “The bottom line is, we don’t know when or if it will erupt again, but we would have adequate warning.”

    *Science paper:
    Modeling ash fall distribution from a Yellowstone supereruption

    See the full article here .

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  • richardmitnick 3:50 pm on February 17, 2016 Permalink | Reply
    Tags: , , , , Yellowstone Caldera   

    From Science Node: “Blue Waters solves Yellowstone mystery” 

    Science Node bloc
    Science Node

    17 Feb, 2016
    Lance Farrell

    Once Lijun Liu saw the proximity of subduction zones to supervolcanoes, the game was afoot. His NSF-funded research project is a harbinger of the age of numerical exploration.

    The Old Faithful geyser at Yellowstone National Park has thrilled park visitors for over a century, but it wasn’t until this year that scientists figured out the geophysical factors powering it.

    With over 2 million visitors annually, Yellowstone remains one of the most popular nature destinations in the US. Spanning an area of almost 3,500 square miles, the park sits atop the Yellowstone Caldera. This caldera is the largest supervolcano in North America, and is responsible for the park’s geothermal activity.

    Caldera at Yellowstone.
    Caldera at Yellowstone

    Until last week, most geologists had explained this activity with the so-called mantle plume hypothesis. This elegant theory proposed an idealized situation where hot columns of mantle rock rose from the core-mantle boundary all the way to the surface, fueling the supervolcano and the geothermal geysers.

    Supervolcanoes worldwide
    Neighborhood watch. A map of the worldwide distribution of supervolcanoes. The light reddish lines are subduction zones, the thick blue lines are mid-ocean ridges, and the size of the circles scales with the magnitude of supervolcanoes. Courtesy Lijun Liu.

    This theory didn’t sit well with Lijun Liu, assistant professor in the department of Geology at the University of Illinois, however. “If you look at the distribution of supervolcanoes globally, you’ll find something very interesting. You will see that most if not all of them are sitting close to a subduction zone,” Liu observes. “This close vicinity made me wonder if there were any internal relations between them, and I thought it was necessary and intriguing to further investigate this.”

    Solving the mystery

    To investigate the formation of Yellowstone volcanism, Liu and co-author Tiffany Leonard turned to the supercomputers at the Texas Advanced Computing Center (TACC) and the National Center for Supercomputing Applications (NCSA). Using Stampede for benchmarking work in 2014, and Blue Waters for modeling in 2015, Liu and Leonard ran 100 models, each requiring a few hundred core hours. The models weren’t too computationally intensive, using only 256 cores and generating only about 10 terabytes of data. In subsequent research, Blue Waters, more attuned to extreme scale calculations, has allowed Liu to scale up experiments up to 10,000 cores.

    Texas Stampede Supercomputer
    TACC Stampede

    Blue Waters supercomputer
    NCSA Blue Waters

    To make the Yellowstone discovery, Liu received valuable technical assistance from the Extreme Science and Engineering Discovery Environment (XSEDE). “We have been using XSEDE machines from very early on, Lonestar, Ranger, and, more lately, Stampede. We got a lot of assistance from XSEDE on installing the code, so by the time we got to this particular project we were pretty fluent using the code.”

    Liu and Leonard’s models, recently published in American Geophysical Union, simulated 40 million years of North American geological activity. By using the most well accepted history of surface plate motion and matching the complex mantle structure seen today with geophysical imaging techniques, Liu’s team imposed two powerful constraints to make sure their models didn’t deviate from reality. The models left little doubt that the flows of mantle beneath Yellowstone are actually modulated by moving plates rather than a single mantle plume.

    Analytical evolution

    According to Liu, prior to high-performance computing (HPC), debates about Yellowstone volcanic activity were like the proverbial blind men touching and describing the elephant. Without HPC, scientists lacked the geophysical data or imaging techniques to see under the surface. Most of the models of that time relied heavily on surface records only.

    “Numerical simulations are so important, especially now we are moving away from simple explanations and analytical solutions,” Liu admits. “We are definitely in the numerical era now. Most of these problems we couldn’t have solved a few years ago.”

    But with the advent of HPC and seismic tomography about 10 years ago, geologists were finally able to peer into the subsurface. By 2010, the scientific landscape had shifted dramatically when the US National Science Foundation (NSF) -funded nationwide seismic experiment called Earthscope unearthed an unprecedented amount of data and corresponding good imagery of the underlying mantle.

    From these images, geologists could see not only localized slow seismic structures called putative plumes, but also widespread fast anomalies often called slabs, or subducting oceanic plates. This breakthrough has created the opportunity for more questions, spawning even more models and hypotheses. Because of the complexity of the system, this is a situation ripe for HPC, Liu reasons.

    Understanding the volcanism powering Yellowstone is important because if this supervolcano erupts, it will affect a large area of the US. “That’s a real threat and a real natural hazard,” Liu quips. “But more seriously, if a mantle plume is powering the Yellowstone flows, then in theory its distribution could be more random — it can form almost anywhere. So it is possible that people in the Midwest who never worry about volcanoes are sitting right above a mantle plume.”

    But if the subduction process is more responsible for Yellowstone, and most of us sit further away from the subduction zone, we can rest a little bit easier.

    Liu’s research was made possible by funding from the NSF, support that procured not only supercomputing time but also student assistance. Providing an educational advantage is the more important benefit of NSF support, Liu says.

    In sum, Liu is convinced of the importance of HPC to the future of geological analysis. “HPC and models with a multidisciplinary theme should be the trend and should be encouraged for future research because this is really the way to solve complex natural systems like Yellowstone.”

    See the full article here .

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  • richardmitnick 2:06 pm on August 29, 2015 Permalink | Reply
    Tags: , , , Yellowstone Caldera   

    From Nautilus: “The Supervolcano Under Yellowstone is Alive and Kicking” 

    Nautilus

    Nautilus

    Aug 29, 2015
    Shannon Hall

    The wind shifts. The stench of rotten eggs makes it nearly impossible to breathe and the hot fog clouds my view. I hold my breath and close my eyes, imagining the fog growing thicker, crushing me. Then without warning the wind clears and I’m enveloped once again in the cold, dry air. The heat feels like a lost dream. I shiver as I analyze my surroundings.

    Before me lies a steaming blue spring with concentric rings of green, yellow and dark red. I turn around to see another pool. But the rising fog is so dense, I can only guess at the existence of blue water below. Sometimes I glimpse bubbles boiling from some unknown source. The pools are a small sampling of the 10,000 geothermal features that dot Yellowstone’s caldera and hint at a mysterious hot spot beneath the crust.

    4
    Yellowstone sits on top of four overlapping calderas. (US NPS)

    1
    Yellowstone Caldera
    2
    Yellowstone Caldera map

    It’s this alien landscape that makes it surprisingly easy to believe that northwestern Wyoming sits directly above a supervolcano — a behemoth far more powerful than your average volcano, with the capacity to eject more than 240 cubic miles of material.

    But why do scientists believe there is a supervolcano hidden below? When I asked Henry Heasler, a park geologist at Yellowstone this question, he waxed philosophical. “Good science is nothing more than a progress report,” he said. “It’s what we know at a certain time with the data that we have.”

    And this year scientists provided one of the most impressive progress reports yet: They peered deep beneath the Earth’s surface and created the first three-dimensional image of the supervolcano’s plumbing. Although they had already imaged a plume, which brings molten rock up from deep below the mantle to a region about 60 kilometers below the surface, and a magma chamber about 10 kilometers below the surface, the new work had found the missing link between the two.

    A second, 11,200-cubic-mile magma chamber connects the plume to the shallower magma chamber. It’s 4.5 times larger than its shallow companion and has enough hot rock to fill the Grand Canyon nearly 14 times.

    Hsin-Hua Huang, a seismologist from the University of Utah and his colleagues used earthquake data to capture this astonishing image. It’s similar to an ultrasound, said Heasler. “We have the skin of a surface—of a person—but we want to see what’s inside.” When earthquakes travel through dense, hot spots they slow down. So if a seismic wave reaches a sensor later than expected, scientists know there’s a low-velocity, and hence denser and hotter, region hidden deep within the Earth.

    3
    “Another thing more worrisome than global warming: Yellowstone super-volcano has 4x more magma than once thought”, from “Watts Up With That”, Alan Watts.

    “If we were just using one pathway—so one earthquake and one seismometer—we couldn’t be able to tell where along that path that low velocity body was. We’d have no idea,” said co-author Jamie Farrell from the University of Utah. That’s where multiple earthquakes and sensors come into play. Huang’s team used 4,849 earthquakes, originating from all parts of the earth, plus 80 seismographs across Yellowstone and beyond, to create a rough three-dimensional picture.

    Their study was also the first to combine both worldwide and local earthquakes. Distant earthquakes allow scientists to image deep structures (any earthquakes originating under India or China will first travel through the Earth’s core before reaching the U.S.) and local earthquakes allow for shallow structures. Combining the two let the team image the deep magma chamber for the first time. Given that natural earthquakes, however, are relatively rare events—even in one of the most active areas in the world—they had to collect 30 years worth of data.

    But seismic tomography isn’t the only way to peer deep underground. GPS satellites can scour the area searching for any ground movement; gravity satellites can look for any changes in the density below; and ground instruments can sample the heat and gases rising from the geothermal features.

    All methods point to a supervolcano that’s very much alive. From 1976 to 1984, GPS satellite data showed that the caldera floor was swelling upward. Magma was flowing from the deeper chamber into the shallow reservoir, causing the above ground to inflate. This influx of hot material, which happens to be less dense, was also reflected in gravity data. To a satellite orbiting directly above the inflow, the Earth will seem to pull on it a little less than expected. Meanwhile ground instruments measured increasing heat and gases rising from the active features.

    Then from 1985 to 1995 the caldera sunk back down about 5.5 inches. Magma was either moving out of the system laterally or the shallow reservoir was simply cooling and contracting, letting gases seep through the surface. Later measurements show that the caldera floor is continuing to swell and sink. But scientists still don’t understand the complex interplay between the supervolcano’s moving parts.

    “I think our next step—hopefully—is to be able to look at some smaller scale features of how these bigger features are connected to each other,” said Farrell. If scientists can determine how the large magma chambers interact with each other, they will better understand how fluids and heat move the Earth. “Then we can start looking at how long it would take for enough material to get from the deep to the shallow [reservoirs] and maybe where we are in the volcanic cycle of eruptions. But we’re not quite there yet.”

    Although past eruptions dot the Earth’s surface from Oregon to Wyoming, it’s hard to infer anything about a future eruption. And Farrell isn’t convinced another super-eruption will happen at all. “The system might be dying,” he said. “The Yellowstone hot spot is moving into thicker, colder continental crust. And it takes a lot more energy to burn through that crust than it did the thinner crust that it’s been burning through for the last 17 million years.”

    But as I watch Yellowstone’s surface boil over before my very eyes it’s hard to believe that the system deep beneath my feet might one day fade away. And as a geyser before me erupts, shooting steam and water tens of feet into the air, I have to wonder if it’s instead slowly building toward another super-eruption. After all, despite Farrell’s uncertainty, he continued to say: “It’s happened in the past, it could happen in the future.”

    See the full article here.

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    Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

     
  • richardmitnick 2:59 pm on April 23, 2015 Permalink | Reply
    Tags: , , Yellowstone Caldera   

    From phys,org: “Scientists see deeper Yellowstone magma” 

    physdotorg
    phys.org

    April 23, 2015
    No Writer Credit

    1
    A new University of Utah study in the journal Science provides the first complete view of the plumbing system that supplies hot and partly molten rock from the Yellowstone hotspot to the Yellowstone supervolcano. The study revealed a gigantic magma reservoir beneath the previously known magma chamber. This cross-section illustration cutting southwest-northeast under Yelowstone depicts the view revealed by seismic imaging. Seismologists say new techniques have provided a better view of Yellowstone’s plumbing system, and that it hasn’t grown larger or closer to erupting. They estimate the annual chance of a Yellowstone supervolcano eruption is 1 in 700,000. Credit: Hsin-Hua Huang, University of Utah

    University of Utah seismologists discovered and made images of a reservoir of hot, partly molten rock 12 to 28 miles beneath the Yellowstone supervolcano, and it is 4.4 times larger than the shallower, long-known magma chamber.

    The hot rock in the newly discovered, deeper magma reservoir would fill the 1,000-cubic-mile Grand Canyon 11.2 times, while the previously known magma chamber would fill the Grand Canyon 2.5 times, says postdoctoral researcher Jamie Farrell, a co-author of the study published online today in the journal Science.

    “For the first time, we have imaged the continuous volcanic plumbing system under Yellowstone,” says first author Hsin-Hua Huang, also a postdoctoral researcher in geology and geophysics. “That includes the upper crustal magma chamber we have seen previously plus a lower crustal magma reservoir that has never been imaged before and that connects the upper chamber to the Yellowstone hotspot plume below.”

    Contrary to popular perception, the magma chamber and magma reservoir are not full of molten rock. Instead, the rock is hot, mostly solid and spongelike, with pockets of molten rock within it. Huang says the new study indicates the upper magma chamber averages about 9 percent molten rock – consistent with earlier estimates of 5 percent to 15 percent melt – and the lower magma reservoir is about 2 percent melt.

    So there is about one-quarter of a Grand Canyon worth of molten rock within the much larger volumes of either the magma chamber or the magma reservoir, Farrell says.

    No increase in the danger

    The researchers emphasize that Yellowstone’s plumbing system is no larger – nor closer to erupting – than before, only that they now have used advanced techniques to make a complete image of the system that carries hot and partly molten rock upward from the top of the Yellowstone hotspot plume – about 40 miles beneath the surface – to the magma reservoir and the magma chamber above it.

    “The magma chamber and reservoir are not getting any bigger than they have been, it’s just that we can see them better now using new techniques,” Farrell says.

    Study co-author Fan-Chi Lin, an assistant professor of geology and geophysics, says: “It gives us a better understanding the Yellowstone magmatic system. We can now use these new models to better estimate the potential seismic and volcanic hazards.”

    The researchers point out that the previously known upper magma chamber was the immediate source of three cataclysmic eruptions of the Yellowstone caldera 2 million, 1.2 million and 640,000 years ago, and that isn’t changed by discovery of the underlying magma reservoir that supplies the magma chamber.

    “The actual hazard is the same, but now we have a much better understanding of the complete crustal magma system,” says study co-author Robert B. Smith, a research and emeritus professor of geology and geophysics at the University of Utah.

    2
    The gorgeous colors of Yellowstone National Park’s Grand Prismatic hot spring are among the park’s myriad hydrothermal features created by the fact Yellowstone is a supervolcano – the largest type of volcano on Earth. A new University of Utah study reports discovery of a huge magma reservoir beneath Yellowstone’s previously known magma chamber. That doesn’t increase the risk of an eruption, but means scientists are getting a better view of Yellowstone’s volcanic plumbing system. Credit: “Windows into the Earth,” Robert B. Smith and Lee J. Siegel

    The three supervolcano eruptions at Yellowstone – on the Wyoming-Idaho-Montana border – covered much of North America in volcanic ash. A supervolcano eruption today would be cataclysmic, but Smith says the annual chance is 1 in 700,000.

    Before the new discovery, researchers had envisioned partly molten rock moving upward from the Yellowstone hotspot plume via a series of vertical and horizontal cracks, known as dikes and sills, or as blobs. They still believe such cracks move hot rock from the plume head to the magma reservoir and from there to the shallow magma chamber.

    Anatomy of a supervolcano

    The study in Science is titled, The Yellowstone magmatic system from the mantle plume to the upper crust. Huang, Lin, Farrell and Smith conducted the research with Brandon Schmandt at the University of New Mexico and Victor Tsai at the California Institute of Technology. Funding came from the University of Utah, National Science Foundation, Brinson Foundation and William Carrico.

    Yellowstone is among the world’s largest supervolcanoes, with frequent earthquakes and Earth’s most vigorous continental geothermal system.

    The three ancient Yellowstone supervolcano eruptions were only the latest in a series of more than 140 as the North American plate of Earth’s crust and upper mantle moved southwest over the Yellowstone hotspot, starting 17 million years ago at the Oregon-Idaho-Nevada border. The hotspot eruptions progressed northeast before reaching Yellowstone 2 million years ago.

    Here is how the new study depicts the Yellowstone system, from bottom to top:

    — Previous research has shown the Yellowstone hotspot plume rises from a depth of at least 440 miles in Earth’s mantle. Some researchers suspect it originates 1,800 miles deep at Earth’s core. The plume rises from the depths northwest of Yellowstone. The plume conduit is roughly 50 miles wide as it rises through Earth’s mantle and then spreads out like a pancake as it hits the uppermost mantle about 40 miles deep. Earlier Utah studies indicated the plume head was 300 miles wide. The new study suggests it may be smaller, but the data aren’t good enough to know for sure.

    — Hot and partly molten rock rises in dikes from the top of the plume at 40 miles depth up to the bottom of the 11,200-cubic mile magma reservoir, about 28 miles deep. The top of this newly discovered blob-shaped magma reservoir is about 12 miles deep, Huang says. The reservoir measures 30 miles northwest to southeast and 44 miles southwest to northeast. “Having this lower magma body resolved the missing link of how the plume connects to the magma chamber in the upper crust,” Lin says.

    — The 2,500-cubic mile upper magma chamber sits beneath Yellowstone’s 40-by-25-mile caldera, or giant crater. Farrell says it is shaped like a gigantic frying pan about 3 to 9 miles beneath the surface, with a “handle” rising to the northeast. The chamber is about 19 miles from northwest to southeast and 55 miles southwest to northeast. The handle is the shallowest, long part of the chamber that extends 10 miles northeast of the caldera.

    Scientists once thought the shallow magma chamber was 1,000 cubic miles. But at science meetings and in a published paper this past year, Farrell and Smith showed the chamber was 2.5 times bigger than once thought. That has not changed in the new study.

    Discovery of the magma reservoir below the magma chamber solves a longstanding mystery: Why Yellowstone’s soil and geothermal features emit more carbon dioxide than can be explained by gases from the magma chamber, Huang says. Farrell says a deeper magma reservoir had been hypothesized because of the excess carbon dioxide, which comes from molten and partly molten rock.

    A better, deeper look at Yellowstone

    As with past studies that made images of Yellowstone’s volcanic plumbing, the new study used seismic imaging, which is somewhat like a medical CT scan but uses earthquake waves instead of X-rays to distinguish rock of various densities. Quake waves go faster through cold rock, and slower through hot and molten rock.

    For the new study, Huang developed a technique to combine two kinds of seismic information: Data from local quakes detected in Utah, Idaho, the Teton Range and Yellowstone by the University of Utah Seismograph Stations and data from more distant quakes detected by the National Science Foundation-funded EarthScope array of seismometers, which was used to map the underground structure of the lower 48 states.

    The Utah seismic network has closely spaced seismometers that are better at making images of the shallower crust beneath Yellowstone, while EarthScope’s seismometers are better at making images of deeper structures.

    “It’s a technique combining local and distant earthquake data better to look at this lower crustal magma reservoir,” Huang says.

    See the full article here.

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    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
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