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- 11,990
A recent article on Yellowstone volcano activity awareness, from the Buffalo Bulletin:
http://www.buffalobulletin.com/arti...in_the_bulletin/doc4d76af3d66be1752582981.txt
Possibly reassuring blog, on whether,or not, the Yellowstone Caldera is safe, from the end of last month:
http://scienceblogs.com/gregladen/2....php?utm_source=networkbanner&utm_medium=link
http://www.buffalobulletin.com/arti...in_the_bulletin/doc4d76af3d66be1752582981.txt
Possibly reassuring blog, on whether,or not, the Yellowstone Caldera is safe, from the end of last month:
http://scienceblogs.com/gregladen/2....php?utm_source=networkbanner&utm_medium=link
- Joined
- Aug 7, 2001
- Messages
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Yellowstone supervolcano fed by bigger plume
By Paul Rincon, Science reporter, BBC News
The underground volcanic plume at Yellowstone in the US may be bigger than previously thought, according to a new study by geologists.
The volcanic hotspot below Yellowstone feeds the hot springs, mud pots and geysers that bring millions of visitors to the US national park each year.
But the Yellowstone "supervolcano" has erupted violently in the distant past and could do so again at some point.
The new study is set to be published in Geophysical Research Letters journal.
In 2009, researchers used seismic waves from earthquakes to build up an image of the hotspot beneath Yellowstone, which straddles the US states of Wyoming, Montana and Idaho.
The authors of the latest work used variations in the electrical conductivity of rocks to produce a new picture of the plume.
This conductivity is a property of the molten silicate rocks and the hot briny water that is naturally present in them.
"It's like comparing ultrasound and MRI in the human body; they are different imaging technologies," says co-author Michael Zhdanov, a professor of geophysics at the University of Utah in Salt Lake City.
The 2009 images, using seismic waves, showed the plume of hot and molten rock dipping downward from Yellowstone at an angle of 60 degrees. This plume extended 240km (150mi) west-northwest to a point at least 660km (410mi) under the Montana-Idaho border.
This was as far as the seismic imaging could "see".
The new study, using electrical conductivity, can only see about 320km (200mi) below ground.
Variations in electrical conductivity reveal the volcanic plume of partly molten rock But it shows the conductive part of the plume dipping more gently, at an angle of perhaps 40 degrees to the west, and extending perhaps 640 km (400 miles) from east to west.
They may look different because the two techniques image slightly different things.
Seismic images highlight materials such as molten or partly molten rock that slow seismic waves, while the geoelectric technique displays briny fluids that conduct electricity.
Co-author Robert B Smith, who is also at University of Utah, said the plume was bigger in the geoelectric picture. He said it could be inferred that there were more fluids than shown by the seismic images.
Despite differences, he says, "this body that conducts electricity is in about the same location with similar geometry as the seismically imaged Yellowstone plume."
The more gentle tilt of the geoelectric plume could suggest that the hot region imaged by the seismic wave technique may be enveloped by a broader, underground envelope of partly molten rock and liquids, the researchers say.
There have been three huge eruptions of the Yellowstone supervolcano: 2.1 million years ago, 1.3 million years ago and 640,000 years ago. Two of these eruptions blanketed a large area of North America with volcanic ash.
The most recent full-scale eruption of the Yellowstone supervolcano ejected some 1,000 cubic km (240 cubic miles) of hot ash and rock into the atmosphere. There have been smaller eruptions in between the largest outpourings; the most recent of these occurred 70,000 years ago.
http://www.bbc.co.uk/news/science-environment-13061779
By Paul Rincon, Science reporter, BBC News
The underground volcanic plume at Yellowstone in the US may be bigger than previously thought, according to a new study by geologists.
The volcanic hotspot below Yellowstone feeds the hot springs, mud pots and geysers that bring millions of visitors to the US national park each year.
But the Yellowstone "supervolcano" has erupted violently in the distant past and could do so again at some point.
The new study is set to be published in Geophysical Research Letters journal.
In 2009, researchers used seismic waves from earthquakes to build up an image of the hotspot beneath Yellowstone, which straddles the US states of Wyoming, Montana and Idaho.
The authors of the latest work used variations in the electrical conductivity of rocks to produce a new picture of the plume.
This conductivity is a property of the molten silicate rocks and the hot briny water that is naturally present in them.
"It's like comparing ultrasound and MRI in the human body; they are different imaging technologies," says co-author Michael Zhdanov, a professor of geophysics at the University of Utah in Salt Lake City.
The 2009 images, using seismic waves, showed the plume of hot and molten rock dipping downward from Yellowstone at an angle of 60 degrees. This plume extended 240km (150mi) west-northwest to a point at least 660km (410mi) under the Montana-Idaho border.
This was as far as the seismic imaging could "see".
The new study, using electrical conductivity, can only see about 320km (200mi) below ground.
Variations in electrical conductivity reveal the volcanic plume of partly molten rock But it shows the conductive part of the plume dipping more gently, at an angle of perhaps 40 degrees to the west, and extending perhaps 640 km (400 miles) from east to west.
They may look different because the two techniques image slightly different things.
Seismic images highlight materials such as molten or partly molten rock that slow seismic waves, while the geoelectric technique displays briny fluids that conduct electricity.
Co-author Robert B Smith, who is also at University of Utah, said the plume was bigger in the geoelectric picture. He said it could be inferred that there were more fluids than shown by the seismic images.
Despite differences, he says, "this body that conducts electricity is in about the same location with similar geometry as the seismically imaged Yellowstone plume."
The more gentle tilt of the geoelectric plume could suggest that the hot region imaged by the seismic wave technique may be enveloped by a broader, underground envelope of partly molten rock and liquids, the researchers say.
There have been three huge eruptions of the Yellowstone supervolcano: 2.1 million years ago, 1.3 million years ago and 640,000 years ago. Two of these eruptions blanketed a large area of North America with volcanic ash.
The most recent full-scale eruption of the Yellowstone supervolcano ejected some 1,000 cubic km (240 cubic miles) of hot ash and rock into the atmosphere. There have been smaller eruptions in between the largest outpourings; the most recent of these occurred 70,000 years ago.
http://www.bbc.co.uk/news/science-environment-13061779
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- Aug 7, 2001
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- 54,631
Super volcanoes 'may be predicted'
By Neil Bowdler, Science and Health reporter, BBC News
The eruption of some of the largest volcanoes on the planet could be predicted several decades before the event, according to researchers.
Analysis of rock crystals from the Greek island of Santorini suggests eruptions are preceded by a fast build-up of magma underground, which might be detected using modern instrumentation.
Such volcanoes can produce enough ash and gas to temporarily change the global climate.
The research is in the journal Nature.
Volcanologists refer to history's largest volcanoes as "caldera-forming eruptions", as the magma ejected is so voluminous that it leaves a massive depression on the Earth's surface and a crater-like structure known as a caldera.
The largest of these volcanoes have been dubbed "super volcanoes" and their eruptions can trigger devastation with global impacts.
Such volcanoes can lie dormant for hundreds of thousands of years before blowing. But while researchers believe seismic data and other readings would give us a few month's notice of such an eruption, the new study suggests we might anticipate these events much earlier.
"When volcanoes awaken and when the magma starts to ascend to the surface, cracking rock as it does, it sends out signals," Prof Tim Druitt of France's Blaise Pascal University and lead researcher told BBC News.
"You get seismic signals, you get deformation of the surface, increasing gas emission at the surface - and this can be detected.
"The question we're addressing here is what's going on at depth prior to these big eruptions. The classical view was that during long repose periods over thousands of years, magma slowly accumulates a few kilometres below the volcano and finally it blows.
"What we're finding is that there's an acceleration phase of magma build-up on a time scale of a few decades, and that's surprisingly short given the thousands of years of repose that have preceded that eruption."
The evidence comes from analysis of crystals in pumice rock from the Santorini site, which the researchers in France, Switzerland and Singapore analysed using modern instrumentation including electron and ion microprobes.
"The changes in composition of the crystals with time provide little histories of how the magma itself has evolved," said Prof Druitt.
"What we found was that all the crystals in the magma grew within a few decades of the eruption."
Caldera-forming eruption sites can be found all over the world, although it is believed that all are currently dormant. They include sites in Yellowstone National Park in the United States, Campi Flegrei in Italy and Santorini and its accompanying islands.
The eruption at the latter site over 3,600 years ago is called the "Minoan" eruption as it occurred at the height of the Minoan civilisation on the nearby island of Crete and was once thought to have caused its collapse, although that is now a moot point.
Predicting such events years rather than months before they happen could prove vital, says Prof Druitt.
"What we're saying is that all caldera volcanoes, even those in remote regions of the globe, should be monitored using highly sensitive modern instruments in order to pick up these deep signals which may suggest reactivation," he said.
"If you had a big eruption of this sort, let's say in the middle of Europe today, the effects would be enormous and a few months might not be enough to get your act together."
Commenting on the paper, Prof David Pyle, a volcanologist from Oxford University said: "This new work on Santorini sheds new light on what happens in the lead-up to the rare catastrophic eruptions, like the Bronze Age 'Minoan' eruption, which happen every 20,000 years or so.
"The new evidence from mineral grains appears to strengthen the idea, which has been developing in recent years, that large magma systems appear to awaken from long periods of repose only shortly (months, years or decades) prior to eruption.
"That is, the magma which eventually erupts appears to rise into position, in the top few kilometres of the crust, only a short time before the eruption begins."
However, he said the next problem was to try to understand what was causing this accelerated build up of magma.
"The challenge for volcanologists is to understand what it is that causes these bursts of melt movement; to understand where the melts have come from, and to be able to recognise their signals before an eruption begins."
http://www.bbc.co.uk/news/science-environment-16834570
By Neil Bowdler, Science and Health reporter, BBC News
The eruption of some of the largest volcanoes on the planet could be predicted several decades before the event, according to researchers.
Analysis of rock crystals from the Greek island of Santorini suggests eruptions are preceded by a fast build-up of magma underground, which might be detected using modern instrumentation.
Such volcanoes can produce enough ash and gas to temporarily change the global climate.
The research is in the journal Nature.
Volcanologists refer to history's largest volcanoes as "caldera-forming eruptions", as the magma ejected is so voluminous that it leaves a massive depression on the Earth's surface and a crater-like structure known as a caldera.
The largest of these volcanoes have been dubbed "super volcanoes" and their eruptions can trigger devastation with global impacts.
Such volcanoes can lie dormant for hundreds of thousands of years before blowing. But while researchers believe seismic data and other readings would give us a few month's notice of such an eruption, the new study suggests we might anticipate these events much earlier.
"When volcanoes awaken and when the magma starts to ascend to the surface, cracking rock as it does, it sends out signals," Prof Tim Druitt of France's Blaise Pascal University and lead researcher told BBC News.
"You get seismic signals, you get deformation of the surface, increasing gas emission at the surface - and this can be detected.
"The question we're addressing here is what's going on at depth prior to these big eruptions. The classical view was that during long repose periods over thousands of years, magma slowly accumulates a few kilometres below the volcano and finally it blows.
"What we're finding is that there's an acceleration phase of magma build-up on a time scale of a few decades, and that's surprisingly short given the thousands of years of repose that have preceded that eruption."
The evidence comes from analysis of crystals in pumice rock from the Santorini site, which the researchers in France, Switzerland and Singapore analysed using modern instrumentation including electron and ion microprobes.
"The changes in composition of the crystals with time provide little histories of how the magma itself has evolved," said Prof Druitt.
"What we found was that all the crystals in the magma grew within a few decades of the eruption."
Caldera-forming eruption sites can be found all over the world, although it is believed that all are currently dormant. They include sites in Yellowstone National Park in the United States, Campi Flegrei in Italy and Santorini and its accompanying islands.
The eruption at the latter site over 3,600 years ago is called the "Minoan" eruption as it occurred at the height of the Minoan civilisation on the nearby island of Crete and was once thought to have caused its collapse, although that is now a moot point.
Predicting such events years rather than months before they happen could prove vital, says Prof Druitt.
"What we're saying is that all caldera volcanoes, even those in remote regions of the globe, should be monitored using highly sensitive modern instruments in order to pick up these deep signals which may suggest reactivation," he said.
"If you had a big eruption of this sort, let's say in the middle of Europe today, the effects would be enormous and a few months might not be enough to get your act together."
Commenting on the paper, Prof David Pyle, a volcanologist from Oxford University said: "This new work on Santorini sheds new light on what happens in the lead-up to the rare catastrophic eruptions, like the Bronze Age 'Minoan' eruption, which happen every 20,000 years or so.
"The new evidence from mineral grains appears to strengthen the idea, which has been developing in recent years, that large magma systems appear to awaken from long periods of repose only shortly (months, years or decades) prior to eruption.
"That is, the magma which eventually erupts appears to rise into position, in the top few kilometres of the crust, only a short time before the eruption begins."
However, he said the next problem was to try to understand what was causing this accelerated build up of magma.
"The challenge for volcanologists is to understand what it is that causes these bursts of melt movement; to understand where the melts have come from, and to be able to recognise their signals before an eruption begins."
http://www.bbc.co.uk/news/science-environment-16834570
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- 54,631
Supervolcanoes 'can grow in just hundreds of years'
The largest volcanoes on our planet may take as little as a few hundred years to form and erupt.
These "supervolcanoes" were thought to exist for as much as 200,000 years before releasing their vast underground pools of molten rock.
Researchers reporting in Plos One have sampled the rock at the supervolcano site of Long Valley in California.
Their findings suggest that the magma pool beneath it erupted within as little as hundreds of years of forming.
That eruption is estimated to have happened about 760,000 years ago, and would have covered half of North America in its ash.
Such super-eruptions can release thousands of cubic kilometres of debris - hundreds of times larger than any eruption seen in the history of humanity.
Eruptions on this scale could release enough ash to influence the global weather for years, and one theory holds that the Lake Toba eruption in Indonesia about 70,000 years ago had long-term effects that nearly wiped out humans altogether.
What little is known about the formation of these supervolcanoes is largely based on the study of crystals of a material called zircon, which contains small amounts of radioactive elements whose age can be estimated using the same techniques used to date archaeological artefacts and dinosaur bones.
Zircon studies to date have suggested that the time between the formation of the enormous magma pools and the eventual super-eruptions can be measured in the hundreds of thousands of years.
Now, Guilherme Gualda of Vanderbilt University and his colleagues present several lines of evidence from the Bishop Tuff deposit at Long Valley, suggesting that the pools are "ephemeral" - lasting as little as 500 years before eruption.
Initially, the magma pools are nearly purely liquid rock, with few bubbles or re-crystallised minerals.
Over time, crystals develop, but the process stops at the point of the eruption. As a result, the characteristic development time of these crystals can also give an estimate of how long a magma pool existed before erupting.
Rather than zircon, the team's target was crystals of the common mineral quartz.
Because the processes and timescales of quartz formation in the extraordinary underground conditions of a magma pool are well-known, the team was able to determine how long the crystals were forming within Long Valley's supervolcano before being spewed out in the eruption.
Their estimates suggest the quartz formed over a range of time between 500 and 3,000 years.
"Our study suggests that when these exceptionally large magma pools form they are ephemeral and cannot exist very long without erupting," said Dr Gualda.
"The fact that the process of magma body formation occurs in historical time, instead of geological time, completely changes the nature of the problem."
At present, geologists do not believe that any of Earth's known giant magma pools are in imminent danger of eruption, but the results suggest future work to better understand how the pools develop, and aim ultimately to predict devastating super-eruptions.
http://www.bbc.co.uk/news/science-environment-18269593
The largest volcanoes on our planet may take as little as a few hundred years to form and erupt.
These "supervolcanoes" were thought to exist for as much as 200,000 years before releasing their vast underground pools of molten rock.
Researchers reporting in Plos One have sampled the rock at the supervolcano site of Long Valley in California.
Their findings suggest that the magma pool beneath it erupted within as little as hundreds of years of forming.
That eruption is estimated to have happened about 760,000 years ago, and would have covered half of North America in its ash.
Such super-eruptions can release thousands of cubic kilometres of debris - hundreds of times larger than any eruption seen in the history of humanity.
Eruptions on this scale could release enough ash to influence the global weather for years, and one theory holds that the Lake Toba eruption in Indonesia about 70,000 years ago had long-term effects that nearly wiped out humans altogether.
What little is known about the formation of these supervolcanoes is largely based on the study of crystals of a material called zircon, which contains small amounts of radioactive elements whose age can be estimated using the same techniques used to date archaeological artefacts and dinosaur bones.
Zircon studies to date have suggested that the time between the formation of the enormous magma pools and the eventual super-eruptions can be measured in the hundreds of thousands of years.
Now, Guilherme Gualda of Vanderbilt University and his colleagues present several lines of evidence from the Bishop Tuff deposit at Long Valley, suggesting that the pools are "ephemeral" - lasting as little as 500 years before eruption.
Initially, the magma pools are nearly purely liquid rock, with few bubbles or re-crystallised minerals.
Over time, crystals develop, but the process stops at the point of the eruption. As a result, the characteristic development time of these crystals can also give an estimate of how long a magma pool existed before erupting.
Rather than zircon, the team's target was crystals of the common mineral quartz.
Because the processes and timescales of quartz formation in the extraordinary underground conditions of a magma pool are well-known, the team was able to determine how long the crystals were forming within Long Valley's supervolcano before being spewed out in the eruption.
Their estimates suggest the quartz formed over a range of time between 500 and 3,000 years.
"Our study suggests that when these exceptionally large magma pools form they are ephemeral and cannot exist very long without erupting," said Dr Gualda.
"The fact that the process of magma body formation occurs in historical time, instead of geological time, completely changes the nature of the problem."
At present, geologists do not believe that any of Earth's known giant magma pools are in imminent danger of eruption, but the results suggest future work to better understand how the pools develop, and aim ultimately to predict devastating super-eruptions.
http://www.bbc.co.uk/news/science-environment-18269593
ramonmercado
CyberPunk
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- Eblana
Toba wssn't too bad.
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- Messages
- 54,631
Yellowstone supervolcano 'even more colossal'
By Rebecca Morelle, Science reporter, BBC World Service
The supervolcano that lies beneath Yellowstone National Park in the US is far larger than was previously thought, scientists report.
A study shows that the magma chamber is about 2.5 times bigger than earlier estimates suggested.
A team found the cavern stretches for more than 90km (55 miles) and contains 200-600 cubic km of molten rock.
The findings are being presented at the American Geophysical Union Fall Meeting in San Francisco.
Prof Bob Smith, from the University of Utah, said: “We’ve been working there for a long time, and we’ve always thought it would be bigger... but this finding is astounding."
If the Yellowstone supervolcano were to blow today, the consequences would be catastrophic.
The last major eruption, which occurred 640,000 years ago, sent ash across the whole of North America, affecting the planet’s climate.
Now researchers believe they have a better idea of what lies beneath the ground.
The team used a network of seismometers that were situated around the park to map the magma chamber.
Dr Jamie Farrell, from the University of Utah, explained: “We record earthquakes in and around Yellowstone, and we measure the seismic waves as they travel through the ground.
“The waves travel slower through hot and partially molten material… with this, we can measure what’s beneath.”
The team found that the magma chamber was colossal. Reaching depths of between 2km and 15km (1 to 9 miles), the cavern was about 90km (55 miles) long and 30km (20 miles) wide.
It pushed further into the north east of the park than other studies had previously shown, holding a mixture of solid and molten rock.
"To our knowledge there has been nothing mapped of that size before,” added Dr Farrell.
The researchers are using the findings to better assess the threat that the volatile giant poses.
“Yes, it is a much larger system… but I don’t think it makes the Yellowstone hazard greater,” explained Prof Bob Smith.
“But what it does tell us is more about the area to the north east of the caldera.”
He added that researchers were unsure when the supervolcano would blow again.
Some believe a massive eruption is overdue, estimating that Yellowstone’s volcano goes off every 700,000 years or so.
But Prof Smith said more data was needed, because there had only been three major eruptions so far. These happened 2.1 million years ago, 1.3 million years ago and 640,000 years ago.
“You can only use the time between eruptions (to work out the frequency), so in a sense you only have two numbers to get to that 700,000 year figure,” he explained.
“How many people would buy something on the stock market on two days of stock data.”
In another study presented at the AGU Fall Meeting, researchers have been looking at other, more ancient volcanic eruptions that happened along the same stretch of continental plate that Yellowstone’s supervolcano sits on.
Dr Marc Reichow, from the University of Leicester, said: “We looked at a time window of between 12.5 to 8 million years ago. We wanted to know how to identify these eruptions and find out how frequently they happened.”
The team found there were fewer volcanic events during this period than had been estimated, but these eruptions were far larger than was previously thought.
Dr Reichow added: “If you look at older volcanoes, it helps to understand what Yellowstone is likely to do.”
http://www.bbc.co.uk/news/science-environment-25312674
By Rebecca Morelle, Science reporter, BBC World Service
The supervolcano that lies beneath Yellowstone National Park in the US is far larger than was previously thought, scientists report.
A study shows that the magma chamber is about 2.5 times bigger than earlier estimates suggested.
A team found the cavern stretches for more than 90km (55 miles) and contains 200-600 cubic km of molten rock.
The findings are being presented at the American Geophysical Union Fall Meeting in San Francisco.
Prof Bob Smith, from the University of Utah, said: “We’ve been working there for a long time, and we’ve always thought it would be bigger... but this finding is astounding."
If the Yellowstone supervolcano were to blow today, the consequences would be catastrophic.
The last major eruption, which occurred 640,000 years ago, sent ash across the whole of North America, affecting the planet’s climate.
Now researchers believe they have a better idea of what lies beneath the ground.
The team used a network of seismometers that were situated around the park to map the magma chamber.
Dr Jamie Farrell, from the University of Utah, explained: “We record earthquakes in and around Yellowstone, and we measure the seismic waves as they travel through the ground.
“The waves travel slower through hot and partially molten material… with this, we can measure what’s beneath.”
The team found that the magma chamber was colossal. Reaching depths of between 2km and 15km (1 to 9 miles), the cavern was about 90km (55 miles) long and 30km (20 miles) wide.
It pushed further into the north east of the park than other studies had previously shown, holding a mixture of solid and molten rock.
"To our knowledge there has been nothing mapped of that size before,” added Dr Farrell.
The researchers are using the findings to better assess the threat that the volatile giant poses.
“Yes, it is a much larger system… but I don’t think it makes the Yellowstone hazard greater,” explained Prof Bob Smith.
“But what it does tell us is more about the area to the north east of the caldera.”
He added that researchers were unsure when the supervolcano would blow again.
Some believe a massive eruption is overdue, estimating that Yellowstone’s volcano goes off every 700,000 years or so.
But Prof Smith said more data was needed, because there had only been three major eruptions so far. These happened 2.1 million years ago, 1.3 million years ago and 640,000 years ago.
“You can only use the time between eruptions (to work out the frequency), so in a sense you only have two numbers to get to that 700,000 year figure,” he explained.
“How many people would buy something on the stock market on two days of stock data.”
In another study presented at the AGU Fall Meeting, researchers have been looking at other, more ancient volcanic eruptions that happened along the same stretch of continental plate that Yellowstone’s supervolcano sits on.
Dr Marc Reichow, from the University of Leicester, said: “We looked at a time window of between 12.5 to 8 million years ago. We wanted to know how to identify these eruptions and find out how frequently they happened.”
The team found there were fewer volcanic events during this period than had been estimated, but these eruptions were far larger than was previously thought.
Dr Reichow added: “If you look at older volcanoes, it helps to understand what Yellowstone is likely to do.”
http://www.bbc.co.uk/news/science-environment-25312674
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rynner2 said:
Well, that just jollied up my afternoon. :wince:
- Joined
- Aug 7, 2001
- Messages
- 54,631
Supervolcano eruption mystery solved
By James Morgan, Science reporter, BBC News, Grenoble
Supervolcanoes like Yellowstone can explode without an earthquake or other external trigger, experts have found.
The sheer volume of liquid magma is enough to cause a catastrophic super-eruption, according to an experiment at the European Synchrotron Radiation Facility (ESRF) in Grenoble.
Simulating the intense heat and pressure inside these "sleeping giants" could help predict a future disaster.
The study by a Swiss team from ETH Zurich appears in Nature Geoscience.
Lead author Wim Malfait, of ETH Zurich said: "We knew the clock was ticking but we didn't know how fast: what would it take to trigger a super-eruption?
"Now we know you don't need any extra factor - a supervolcano can erupt due to its enormous size alone.
"Once you get enough melt, you can start an eruption just like that."
There are about 20 known supervolcanoes on Earth - including Lake Toba in Indonesia, Lake Taupo in New Zealand, and the somewhat smaller Phlegraean Fields near Naples, Italy.
Super-eruptions occur rarely - only once every 100,000 years on average. But when they do occur, they have a devastating impact on Earth's climate and ecology.
When a supervolcano erupted 600,000 years ago in Wyoming, in what today is Yellowstone National Park, it ejected more than 1,000 cubic km of ash and lava into the atmosphere - enough to bury a large city to a depth of a few kilometres
This ejection was 100 times bigger than Mt Pinatubo in the Philippines in 1992 and dwarfs even historic eruptions like Krakatoa (1883).
"This is something that, as a species, we will eventually have to deal with. It will happen in future," said Dr Malfait.
"You could compare it to an asteroid impact - the risk at any given time is small, but when it happens the consequences will be catastrophic."
Being able to predict such a catastrophe is obviously critical. But the trigger has remained elusive - because the process is different from conventional volcanoes like Pinatubo and Mt St Helens.
One possible mechanism was thought to be the overpressure in the magma chamber generated by differences between the less dense molten magma and more dense rock surrounding it.
"The effect is comparable to holding a football under water. When you release it, the air-filled ball is forced upwards by the denser water around it," said Wim Malfait, of ETH Zurich.
But whether this buoyancy effect alone was enough was not known. It could be that an an additional trigger - such as a sudden injection of magma, an infusion of water vapour, or an earthquake - was required.
To simulate the intense pressure and heat in the caldera of a supervolcano, the researchers visited ESRF in Grenoble, where they used an experimental station called the high pressure beamline.
They loaded synthetic magma into a diamond capsule and fired high-energy X-rays inside - to probe for changes as the mixture reached critically high pressures.
"If we measure the density difference from solid to liquid magma we can calculate the pressure needed to provoke a spontaneous eruption," Mohamed Mezouar, an ESRF scientist, told BBC News.
"To recreate the conditions in the Earth's crust is no trivial matter, but with the right vessel we can keep the liquid magma stable up to 1,700C and 36,000 atmospheres".
The experiment showed that the transition from solid to liquid magma creates a pressure which can crack more than 10 kilometres of Earth's crust above the volcano chamber.
"Magma penetrating into the cracks will eventually reach the Earth's surface. And as it rises, it will expand violently - causing an explosion," said Carmen Sanchez-Valle, also of ETH Zurich.
But if Yellowstone happened to be on the brink of an eruption, the good news is that we will still see a warning, Dr Malfait told BBC News.
"The ground would probably rise hundreds of metres - a lot more than it does now.
"We think Yellowstone currently has 10-30% partial melt, and for the overpressure to be high enough to erupt would take about 50%."
In a separate study in the same journal, a team led by Luca Caricchi of the University of Geneva used a mathematical model to explain the differences between conventional volcanoes and supervolcanoes.
They showed that "hyperactive" common volcanoes can evolve over time into "sleeping" supervolcanoes.
"Taken together, Malfait and Caricchi paint a provocative picture. Their results imply that rare, giant super-eruptions and smaller, more frequent events reflect a transition in the essential driving forces for volcanism," said Mark Jellinek, of the University of British Columbia, writing in Nature.
http://www.bbc.co.uk/news/science-environment-25598050
By James Morgan, Science reporter, BBC News, Grenoble
Supervolcanoes like Yellowstone can explode without an earthquake or other external trigger, experts have found.
The sheer volume of liquid magma is enough to cause a catastrophic super-eruption, according to an experiment at the European Synchrotron Radiation Facility (ESRF) in Grenoble.
Simulating the intense heat and pressure inside these "sleeping giants" could help predict a future disaster.
The study by a Swiss team from ETH Zurich appears in Nature Geoscience.
Lead author Wim Malfait, of ETH Zurich said: "We knew the clock was ticking but we didn't know how fast: what would it take to trigger a super-eruption?
"Now we know you don't need any extra factor - a supervolcano can erupt due to its enormous size alone.
"Once you get enough melt, you can start an eruption just like that."
There are about 20 known supervolcanoes on Earth - including Lake Toba in Indonesia, Lake Taupo in New Zealand, and the somewhat smaller Phlegraean Fields near Naples, Italy.
Super-eruptions occur rarely - only once every 100,000 years on average. But when they do occur, they have a devastating impact on Earth's climate and ecology.
When a supervolcano erupted 600,000 years ago in Wyoming, in what today is Yellowstone National Park, it ejected more than 1,000 cubic km of ash and lava into the atmosphere - enough to bury a large city to a depth of a few kilometres
This ejection was 100 times bigger than Mt Pinatubo in the Philippines in 1992 and dwarfs even historic eruptions like Krakatoa (1883).
"This is something that, as a species, we will eventually have to deal with. It will happen in future," said Dr Malfait.
"You could compare it to an asteroid impact - the risk at any given time is small, but when it happens the consequences will be catastrophic."
Being able to predict such a catastrophe is obviously critical. But the trigger has remained elusive - because the process is different from conventional volcanoes like Pinatubo and Mt St Helens.
One possible mechanism was thought to be the overpressure in the magma chamber generated by differences between the less dense molten magma and more dense rock surrounding it.
"The effect is comparable to holding a football under water. When you release it, the air-filled ball is forced upwards by the denser water around it," said Wim Malfait, of ETH Zurich.
But whether this buoyancy effect alone was enough was not known. It could be that an an additional trigger - such as a sudden injection of magma, an infusion of water vapour, or an earthquake - was required.
To simulate the intense pressure and heat in the caldera of a supervolcano, the researchers visited ESRF in Grenoble, where they used an experimental station called the high pressure beamline.
They loaded synthetic magma into a diamond capsule and fired high-energy X-rays inside - to probe for changes as the mixture reached critically high pressures.
"If we measure the density difference from solid to liquid magma we can calculate the pressure needed to provoke a spontaneous eruption," Mohamed Mezouar, an ESRF scientist, told BBC News.
"To recreate the conditions in the Earth's crust is no trivial matter, but with the right vessel we can keep the liquid magma stable up to 1,700C and 36,000 atmospheres".
The experiment showed that the transition from solid to liquid magma creates a pressure which can crack more than 10 kilometres of Earth's crust above the volcano chamber.
"Magma penetrating into the cracks will eventually reach the Earth's surface. And as it rises, it will expand violently - causing an explosion," said Carmen Sanchez-Valle, also of ETH Zurich.
But if Yellowstone happened to be on the brink of an eruption, the good news is that we will still see a warning, Dr Malfait told BBC News.
"The ground would probably rise hundreds of metres - a lot more than it does now.
"We think Yellowstone currently has 10-30% partial melt, and for the overpressure to be high enough to erupt would take about 50%."
In a separate study in the same journal, a team led by Luca Caricchi of the University of Geneva used a mathematical model to explain the differences between conventional volcanoes and supervolcanoes.
They showed that "hyperactive" common volcanoes can evolve over time into "sleeping" supervolcanoes.
"Taken together, Malfait and Caricchi paint a provocative picture. Their results imply that rare, giant super-eruptions and smaller, more frequent events reflect a transition in the essential driving forces for volcanism," said Mark Jellinek, of the University of British Columbia, writing in Nature.
http://www.bbc.co.uk/news/science-environment-25598050
Vardoger
Make mine a 99
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Bardarbunga is one big fucking volcano, probably a supervolcano.
These images are supposed to show Iceland from space filmed in the afternoon.
https://twitter.com/metdesk/status/522284741740216320
The lava field below the ice sheet is humongous if this is a heat measurement.
The fissure from which lava is coming these days are pretty small compared to what these images shows.
These images are supposed to show Iceland from space filmed in the afternoon.
https://twitter.com/metdesk/status/522284741740216320
The lava field below the ice sheet is humongous if this is a heat measurement.
The fissure from which lava is coming these days are pretty small compared to what these images shows.
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Oh, great ... 
It would appear supervolcanic eruptions (aka 'supereruptions') occur more frequently than previously believed ...
FULL STORY: http://www.newsweek.com/catastrophic-civilization-ending-supervolcano-eruption-725618
It would appear supervolcanic eruptions (aka 'supereruptions') occur more frequently than previously believed ...
FULL STORY: http://www.newsweek.com/catastrophic-civilization-ending-supervolcano-eruption-725618
Mythopoeika
I am a meat popsicle
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Ahhh, well. Nice knowing you all.
escargot
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This is what will end civilisation: not pollution or nuclear war or global warming, but a powerful volcano. Dust from it will be carried on the wind all over the world and first stop engines - no cars, trains or planes - and then it will move into the upper atmosphere and block out the sun, and crops will fail.
hunck
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..and that's the weather forecast for the next few days. Now back to John Humphreys in the studio..
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There seems to be some wilful misreading of the facts abroad recently. Most simply that 'movement' and 'activity' = increased likeliness of BOOM. This lays out the actual facts:
A chunk of Yellowstone the size of Chicago has been pulsing. Why?
An injection of magma under Norris Geyser Basin may be why the region is five inches higher today than it was 20 years ago.
BY ROBIN GEORGE ANDREWS
In northwestern Wyoming, in the center of Yellowstone National Park, a bubbling caldera is the scar of a 640,000-year-old, gargantuan volcanic eruption. The 3,472-square-mile park encompassing the caldera is filled with geologic wonderlands of sprouting geysers and effervescing pools, all ultimately driven by magma and superheated fluids churning in the rock below the surface.
One of these areas, Norris Geyser Basin to the northwest of the caldera, contains more than 500 hydrothermal features. These tempestuous geysers and pools often change from day to day, but a much larger transformation has been taking place as well: For more than two decades, an area larger than Chicago centered near the basin has been inflating and deflating by several inches in erratic bursts. In a hyperactive volcanic region like Yellowstone, the exact causes of any specific movement are difficult to pin down. But a recent study in the Journal of Geophysical Research: Solid Earth may help explain why this pocket of land has been breathing in and out.
“In all likelihood, Norris has been a center of deformation for a very long time,” says Daniel Dzurisin, a research geologist at the U.S. Geological Survey’s Cascades Volcano Observatory and one of the co-authors of the new research.
Scientists used decades of satellite-based radar and GPS data of Norris Geyser Basin to model what may have occurred below its surface based on the changes above. In the late 1990s, a body of magma intruded beneath Norris, and fluids trapped within the magma bubbled out and made their way through the rocky labyrinth above them. As the fluids got stuck and pressure built up, the ground would rise, and when the fluids were able to escape elsewhere, the ground deflated. Today, magma-derived fluids could sit close to the surface, just a mile or so below the ground.
To be clear, the new research does not indicate that the supervolcano that created Yellowstone’s caldera—which last erupted 640,000 years ago—is any more likely to erupt now. Instead, these geologic movements may help explain why the park’s Steamboat Geyser, the world’s tallest active geyser, has been erupting at a record-breaking pace since March 2018. Researchers also speculate that the changes below Norris may mean a slightly increased chance of hydrothermal explosions taking place in the basin. (Get a peek inside Yellowstone's supervolcano.)
Much More With Numerous Links to Scientific Studies:
https://www.nationalgeographic.com/science/2020/03/chunk-yellowstone-size-chicago-has-been-pulsing/
A chunk of Yellowstone the size of Chicago has been pulsing. Why?
An injection of magma under Norris Geyser Basin may be why the region is five inches higher today than it was 20 years ago.
BY ROBIN GEORGE ANDREWS
In northwestern Wyoming, in the center of Yellowstone National Park, a bubbling caldera is the scar of a 640,000-year-old, gargantuan volcanic eruption. The 3,472-square-mile park encompassing the caldera is filled with geologic wonderlands of sprouting geysers and effervescing pools, all ultimately driven by magma and superheated fluids churning in the rock below the surface.
One of these areas, Norris Geyser Basin to the northwest of the caldera, contains more than 500 hydrothermal features. These tempestuous geysers and pools often change from day to day, but a much larger transformation has been taking place as well: For more than two decades, an area larger than Chicago centered near the basin has been inflating and deflating by several inches in erratic bursts. In a hyperactive volcanic region like Yellowstone, the exact causes of any specific movement are difficult to pin down. But a recent study in the Journal of Geophysical Research: Solid Earth may help explain why this pocket of land has been breathing in and out.
“In all likelihood, Norris has been a center of deformation for a very long time,” says Daniel Dzurisin, a research geologist at the U.S. Geological Survey’s Cascades Volcano Observatory and one of the co-authors of the new research.
Scientists used decades of satellite-based radar and GPS data of Norris Geyser Basin to model what may have occurred below its surface based on the changes above. In the late 1990s, a body of magma intruded beneath Norris, and fluids trapped within the magma bubbled out and made their way through the rocky labyrinth above them. As the fluids got stuck and pressure built up, the ground would rise, and when the fluids were able to escape elsewhere, the ground deflated. Today, magma-derived fluids could sit close to the surface, just a mile or so below the ground.
To be clear, the new research does not indicate that the supervolcano that created Yellowstone’s caldera—which last erupted 640,000 years ago—is any more likely to erupt now. Instead, these geologic movements may help explain why the park’s Steamboat Geyser, the world’s tallest active geyser, has been erupting at a record-breaking pace since March 2018. Researchers also speculate that the changes below Norris may mean a slightly increased chance of hydrothermal explosions taking place in the basin. (Get a peek inside Yellowstone's supervolcano.)
Much More With Numerous Links to Scientific Studies:
https://www.nationalgeographic.com/science/2020/03/chunk-yellowstone-size-chicago-has-been-pulsing/
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New research has identified two previously unrecognized Yellowstone (and associated volcanic province) super-eruptions from the Miocene.
Inclusion of these newly identified super-eruptions suggests the Yellowstone hotspot may actually be waning in intensity. It also suggests the updated frequency of super-eruptions points to a longer - not shorter - average interval between such events. FWIW this also casts doubts on prior estimates and projections, some of which had been spun in the popular press to claim the next Yellowstone super-eruption is "overdue."
FULL STORY: https://www.sciencedaily.com/releases/2020/06/200603132516.htm
Inclusion of these newly identified super-eruptions suggests the Yellowstone hotspot may actually be waning in intensity. It also suggests the updated frequency of super-eruptions points to a longer - not shorter - average interval between such events. FWIW this also casts doubts on prior estimates and projections, some of which had been spun in the popular press to claim the next Yellowstone super-eruption is "overdue."
FULL STORY: https://www.sciencedaily.com/releases/2020/06/200603132516.htm
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Here are the bibliographic particulars and abstract for the report cited above. The full article (in PDF format) is accessible at the link below.
Discovery of two new super-eruptions from the Yellowstone hotspot track (USA): Is the Yellowstone hotspot waning?
Thomas R. Knott; Michael J. Branney; Marc K. Reichow; David R. Finn; Simon Tapster; Robert S. Coe
Geology (2020)
https://doi.org/10.1130/G47384.1
Super-eruptions are amongst the most extreme events to affect Earth’s surface, but too few examples are known to assess their global role in crustal processes and environmental impact. We demonstrate a robust approach to recognize them at one of the best-preserved intraplate large igneous provinces, leading to the discovery of two new super-eruptions. Each generated huge and unusually hot pyroclastic density currents that sterilized extensive tracts of Idaho and Nevada in the United States. The ca. 8.99 Ma McMullen Creek eruption was magnitude 8.6, larger than the last two major eruptions at Yellowstone (Wyoming). Its volume exceeds 1700 km3, covering ≥12,000 km2. The ca. 8.72 Ma Grey’s Landing eruption was even larger, at magnitude of 8.8 and volume of ≥2800 km3. It covers ≥23,000 km2 and is the largest and hottest documented eruption from the Yellowstone hotspot. The discoveries show the effectiveness of distinguishing and tracing vast deposit sheets by combining trace-element chemistry and mineral compositions with field and paleomagnetic characterization. This approach should lead to more discoveries and size estimates, here and at other provinces. It has increased the number of known super-eruptions from the Yellowstone hotspot, shows that the temporal framework of the magmatic province needs revision, and suggests that the hotspot may be waning.
SOURCE: https://pubs.geoscienceworld.org/gs.../Discovery-of-two-new-supereruptions-from-the
FULL ARTICLE: Accessible via the link above.
Discovery of two new super-eruptions from the Yellowstone hotspot track (USA): Is the Yellowstone hotspot waning?
Thomas R. Knott; Michael J. Branney; Marc K. Reichow; David R. Finn; Simon Tapster; Robert S. Coe
Geology (2020)
https://doi.org/10.1130/G47384.1
Super-eruptions are amongst the most extreme events to affect Earth’s surface, but too few examples are known to assess their global role in crustal processes and environmental impact. We demonstrate a robust approach to recognize them at one of the best-preserved intraplate large igneous provinces, leading to the discovery of two new super-eruptions. Each generated huge and unusually hot pyroclastic density currents that sterilized extensive tracts of Idaho and Nevada in the United States. The ca. 8.99 Ma McMullen Creek eruption was magnitude 8.6, larger than the last two major eruptions at Yellowstone (Wyoming). Its volume exceeds 1700 km3, covering ≥12,000 km2. The ca. 8.72 Ma Grey’s Landing eruption was even larger, at magnitude of 8.8 and volume of ≥2800 km3. It covers ≥23,000 km2 and is the largest and hottest documented eruption from the Yellowstone hotspot. The discoveries show the effectiveness of distinguishing and tracing vast deposit sheets by combining trace-element chemistry and mineral compositions with field and paleomagnetic characterization. This approach should lead to more discoveries and size estimates, here and at other provinces. It has increased the number of known super-eruptions from the Yellowstone hotspot, shows that the temporal framework of the magmatic province needs revision, and suggests that the hotspot may be waning.
SOURCE: https://pubs.geoscienceworld.org/gs.../Discovery-of-two-new-supereruptions-from-the
FULL ARTICLE: Accessible via the link above.
Mythopoeika
I am a meat popsicle
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Well, that's a relief.
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New research suggests the reactivation of Yellowstone's Steamboat Geyser doesn't justify worrying the Yellowstone volcanic province is going to erupt anytime soon.
FULL STORY: https://scitechdaily.com/is-reawake...for-explosive-yellowstone-volcanic-eruptions/
FULL STORY: https://scitechdaily.com/is-reawake...for-explosive-yellowstone-volcanic-eruptions/
Mythopoeika
I am a meat popsicle
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Maybe the revival of this geyser is a good thing? Relieving the pressure this way may prevent a gigantic explosion from occurring.
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Oh, great ...
FULL STORY: https://www.sciencealert.com/unnerv...no-warning-for-the-next-supervolcano-eruption
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Here are the bibliographic details and significance statement for the published report on the Toba study.
Liu, Ping-Ping et al
"Growth and thermal maturation of the Toba magma reservoir."
Proceedings of the National Academy of Sciences 118.45 (2021)
e2101695118. Web. 05 Nov. 2021.
Significance
Understanding the thermal state of magma reservoirs before supereruptions is crucial for interpreting the processes leading to such catastrophic events. Here, we show that the two supereruptions of Toba were preceded and followed by protracted magma influx at relatively constant average volumetric rate over the past 2.2 My. This suggests that increased magma flux is not essential before supereruptions. Instead, long-term thermal maturation of the magma reservoir related to significant magma pulses primes the system for eruption. Importantly, our results indicate that significant variations of monitoring parameters, such as increased surface deformation or degassing, may not occur before supereruptions. Our method can be widely applied to other large silicic magmatic systems to evaluate their potential to feed a supereruption.
SOURCE: https://www.pnas.org/content/118/45/e2101695118
Liu, Ping-Ping et al
"Growth and thermal maturation of the Toba magma reservoir."
Proceedings of the National Academy of Sciences 118.45 (2021)
e2101695118. Web. 05 Nov. 2021.
Significance
Understanding the thermal state of magma reservoirs before supereruptions is crucial for interpreting the processes leading to such catastrophic events. Here, we show that the two supereruptions of Toba were preceded and followed by protracted magma influx at relatively constant average volumetric rate over the past 2.2 My. This suggests that increased magma flux is not essential before supereruptions. Instead, long-term thermal maturation of the magma reservoir related to significant magma pulses primes the system for eruption. Importantly, our results indicate that significant variations of monitoring parameters, such as increased surface deformation or degassing, may not occur before supereruptions. Our method can be widely applied to other large silicic magmatic systems to evaluate their potential to feed a supereruption.
SOURCE: https://www.pnas.org/content/118/45/e2101695118
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In case you need something else to fret about ... These two researchers remind us that the danger of volcanic super-eruption(s) is as potentially great as the risk of a major asteroid strike.
PUBLISHED ARTICLE (On Which This Is Based): https://www.nature.com/articles/d41586-022-02177-x
FULL STORY: https://www.sciencealert.com/the-world-is-not-ready-for-the-next-super-eruption-scientists-warn
PUBLISHED ARTICLE (On Which This Is Based): https://www.nature.com/articles/d41586-022-02177-x
Sharon Hill
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When are we ever "ready" for that?
I recall seeing the volcanologists got a bit of flak for this framing, which sounds like scare-mongering, but now I can't find where I saw that.
I recall seeing the volcanologists got a bit of flak for this framing, which sounds like scare-mongering, but now I can't find where I saw that.
Sharon Hill
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Just a little bit terrifying...
The Campi Flegrei volcano in southern Italy has become weaker and more prone to rupturing, according to a new study by researchers at UCL and Italy’s National Research Institute for Geophysics and Volcanology (INGV).
Lead author Professor Christopher Kilburn (UCL Earth Sciences) said: “Our new study confirms that Campi Flegrei is moving closer to rupture. However, this does not mean an eruption is guaranteed. The rupture may open a crack through the crust, but the magma still needs to be pushing up at the right location for an eruption to occur.
https://www.ucl.ac.uk/news/2023/jun/crust-campi-flegrei-volcano-weakening
Here's the paper in Nature.
https://www.nature.com/articles/s43247-023-00842-1#Sec2
Crust of Campi Flegrei volcano is weakening
9 June 2023The Campi Flegrei volcano in southern Italy has become weaker and more prone to rupturing, according to a new study by researchers at UCL and Italy’s National Research Institute for Geophysics and Volcanology (INGV).
Lead author Professor Christopher Kilburn (UCL Earth Sciences) said: “Our new study confirms that Campi Flegrei is moving closer to rupture. However, this does not mean an eruption is guaranteed. The rupture may open a crack through the crust, but the magma still needs to be pushing up at the right location for an eruption to occur.
https://www.ucl.ac.uk/news/2023/jun/crust-campi-flegrei-volcano-weakening
Here's the paper in Nature.
https://www.nature.com/articles/s43247-023-00842-1#Sec2
