From Discover Magazine: “Some Volcanoes Create Undersea Bubbles Up to a Quarter Mile Wide”

DiscoverMag

From Discover Magazine

October 18, 2019
Meeri Kim

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A plume of steam flows upward from Bogoslof volcano, a partially submerged volcano that created giant underwater bubbles when it erupted in 2017. (Credit: Dave Withrow, Alaska Volcano Observatory)

As a geophysicist at the Alaska Volcano Observatory, John Lyons spends much of his days trying to decipher the music of volcanic eruptions. Sensitive microphones scattered across the Aleutian Arc — a chain of over 80 volcanoes that sweeps westward from the Alaskan peninsula — eavesdrop on every explosion, tremor and burp.

In 2017, the partially submerged volcano Bogoslof erupted, sending clouds of ash and water vapor as high as 7 miles above sea level and significantly disrupting air traffic in the area. Throughout the nine months that the volcano remained active, the observatory’s microphones picked up a strange, low-and-slow melody that repeated over 250 times.

“Instead of happening very fast and with high frequencies, which is typical for explosive eruptions, these signals were really low frequency, and some of them had periods up to 10 seconds,” said Lyons.

The source of the odd sounds remained a mystery for months, until one of Lyons’ colleagues stumbled upon a striking description of the ocean’s surface during a 1908 Bogoslof eruption, observed from a Navy ship. As reported in a 1911 issue of The Technical World Magazine, officers reported seeing a “gigantic dome-like swelling, as large as the dome of the capitol at Washington [D.C.].” The dome shrank and grew until finally culminating in “great clouds of smoke and steam … gradually growing in immensity until the spellbound spectators began to fear they would be engulfed in a terrific cataclysm.”

Lyons and his colleagues wondered if the low-frequency signals they heard could correspond to huge bubbles of gas forming just under the surface of the ocean. They modeled the sounds as overpressurized gas bubbles near the water-air interface, inspired by studies of magmatic bubbles that formed at the air-magma interface of Italy’s Stromboli volcano, which emitted similar signals but of shorter duration.

Their results, published in the journal Nature Geoscience on Monday, suggest that submerged volcanic explosions can indeed produce Capitol dome-sized bubbles — and according to their calculations, these would be considered on the smaller side. The bubble diameters from the 2017 Bogoslof eruption were estimated to range from 100 to 440 meters (328 to 1,444 feet), with the largest stretching more than a quarter-mile across.

“It’s hard to imagine a bubble so big, but the volumes of gas that we calculated to be inside the bubbles are similar to the volumes of gas that have been calculated for [open air] explosions,” said Lyons. “Take the big cloud of gas and ash that’s emitted from a volcano and imagine sticking that underwater. It has to come out somehow.”

The researchers propose that gargantuan bubbles would arise from the unique interaction between cold seawater and hot volcanic matter. As magma begins to ascend from the submarine vent, the seawater rapidly chills the outer layer, producing a gas-tight cap over the vent. This rind of semicooled lava eventually pops like a champagne cork as a result of the pressure in the vent, releasing the gases trapped underneath as a large bubble. The bubble in the water grows larger and eventually pokes out into the air. After a few rounds of expansion and contraction, the bubble breaks, releasing the gas and producing eruption clouds in the atmosphere.

The low-frequency sounds come from the bubble alternately growing and shrinking as it attempts to find an equilibrium between the expansion of the gas inside and the constriction of the shell, made up of mostly seawater and volcanic ash. The findings represent the first time such activity has been recorded with infrasound monitoring, which detects sound waves traveling in the air below the threshold of human hearing. Researchers are increasingly turning to the technique as a way to supplement traditional seismic data and gain more insight into eruption dynamics.

“I find the work groundbreaking and impactful,” said Jeffrey B. Johnson, a geophysicist at Boise State University in Idaho who was not involved in the study. “Giant bubbles which defy the imagination are able to oscillate and produce sound that you can record several kilometers away.”

Aside from the 1908 Bogoslof eruption, two other recorded observations match this phenomenon of giant bubbles emerging from the sea: the 1952-53 eruption of the Myojin volcano in Japan and the 1996 eruption of the Karymsky volcano in Russia. A report on the latter event describes “a rapidly rising, dark grey, smooth-surfaced bulbous mass of expanding gas and pyroclasts, probably maintained by surface tension within a shell of water.” The bubble grew to an estimated height of 450 meters above the sea surface.

To witness these bubbles in real life is a challenge, since submerged volcanoes are often remote and surrounded by lots of ocean — not to mention, one’s timing has to be perfect. But Lyons hopes to follow up on this work by studying the dynamics of similar systems that are more approachable and directly observable, such as geysers or mud pots. He envisions listening in on the sounds coming from these types of bubbles to check the validity of certain assumptions they had to make in their model, such as the viscosity of the water.

See the full article here .

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From Science Alert: “The Biggest Volcano on Io May Be About to Erupt, And Scientists Are Watching Closely”

ScienceAlert

18 SEP 2019
MICHELLE STARR

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Voyager 1 image of the Loki patera. (NASA/JPL/USGS)

NASA/Voyager 1

The biggest volcano on Jupiter’s moon Io could be about to blow. Decades of observation have revealed a periodic cycle in the volcano’s eruptions; according to past behaviour, it’s due for the next one any day.

That potential burst of activity – or lack thereof – could help us to better understand the volcano and Io itself, the most volcanically active object in the Solar System.

The massive volcano, called Loki, was originally discovered to have a cycle of around 540 days. This was based on years of observations between 1988 and 2000, described in a 2002 paper [Geophysical Research Letters] led by physicist and planetary scientist Julie Rathbun of the Planetary Science Institute.

At the start of the eruption, Loki would brighten, and remain bright for around 230 days before falling darker again. Then, the cycle would repeat. This was happening like clockwork until 2001, when the volcano stopped brightening and dimming.

Then, in 2013, Loki started up again, but on a slightly shorter cycle – 475 days, instead of 540. It’s been on a 475-day cycle ever since.

“If this behaviour remains the same, Loki should erupt in September 2019,” Rathbun said. “We correctly predicted that the last eruption would occur in May of 2018.”

Rathbun and her team interpreted Loki as a lake of lava in a crater-like depression called a patera about 200 kilometres (124 miles) across. As the cooling crust on the surface of the lake becomes gravitationally unstable and collapses into it, the pool “overturns”, flooded by fresh lava.

This was supported by observations reported in 2017 that saw waves of lava slowly rolling across the patera – a process that can take up to 230 days.

What caused the hiatus in this cycle between 2001 and 2013 is not yet known, but one possible explanation could implicate changes in the volatile content in the magma, which affects the density of both magma and crust. Even a small change can produce large variations in how long the crust takes to sink.

The last eruption started sometime between 23 May and 6 June 2018. That means the 475-day window is between 9 and 24 September. It may have already started.

“Volcanoes are so difficult to predict because they are so complicated. Many things influence volcanic eruptions, including the rate of magma supply, the composition of the magma – particularly the presence of bubbles in the magma, the type of rock the volcano sits in, the fracture state of the rock, and many other issues,” Rathbun said.

“We think that Loki could be predictable because it is so large. Because of its size, basic physics are likely to dominate when it erupts, so the small complications that affect smaller volcanoes are likely to not affect Loki as much.”

Rathbun presented her findings at the EPSC-DPS Joint Meeting 2019 in Geneva.

See the full article here .


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From EarthSky and Eos: “Volcanic Eruption Creates Temporary Islands of Pumice”

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From EarthSky

From AGU
Eos news bloc

From Eos

6 September 2019
Katherine Kornei, Eos
Eleanor Imster, EarthSky

Sailing through rocks is anything but quiet. Last month, vessels in the South Pacific clinked and clanked their way through pumice spewed out from an undersea volcano. These temporary islands of volcanic rock, shaped and propelled by ocean currents, wind, and waves, provide a literal toehold for marine life like barnacles, coral, macroalgae, and mollusks.

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Last month, rafts of pumice, spewed from an undersea volcano and spanning an area about the size of Washington, D.C., appeared in the South Pacific. Satellite image of a pumice raft floating near the Kingdom of Tonga. Image via NASA Earth Observatory.

In early August, an unnamed volcano near the Kingdom of Tonga erupted roughly 40 meters underwater. The eruption sent pieces of gray pumice—porous rock filled with gas bubbles—floating to the surface. This volcanic debris, some fragments as large as beach balls, then aggregated into pumice “rafts” spanning roughly 200 square kilometers.

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August 13, 2019. See detail below. Image via NASA Earth Observatory.

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Detail of above image, taken August 13, 2019. Image via NASA Earth Observatory.

Several sailing crews have encountered the rocks.

“We were in a large area surrounded as far as the eye could see,” said Rachel Mackie, the purser and chef of Olive, a private vessel that sailed into a raft on 9 August near Late Island. There was a strong smell of sulfur, said Mackie, and Olive took a beating. “When the larger rocks hit the steel hull, it reverberated.”

Several sailing crews have encountered the rocks.

“We were in a large area surrounded as far as the eye could see,” said Rachel Mackie, the purser and chef of Olive, a private vessel that sailed into a raft on 9 August near Late Island. There was a strong smell of sulfur, said Mackie, and Olive took a beating. “When the larger rocks hit the steel hull, it reverberated.”

Pumice rafts aren’t that common, said Martin Jutzeler, a volcanologist at the University of Tasmania in Hobart. “We see about two per decade.”

Not all undersea eruptions produce them, but the rafts that do form tend to stick around. They can last for months or years until the pumice abrades itself into dust or finally sinks. And floating pumice can traverse long distances—when the same unnamed volcano near Tonga erupted in 2001, the pumice raft it created eventually arrived in Queensland, Australia, said Jutzeler.

These transient, movable islands play an important role in marine ecosystems, scientists agree. Barnacles, coral, and macroalgae have all been found clinging to pumice, riding the waves en route to a new home.

“It’s a perfect little substrate,” said Jutzeler.

In 2012, Scott Bryan, a geologist at the Queensland University of Technology in Australia, and his colleagues showed that pumice rafts can significantly increase the dispersal of marine organisms. Bryan and his team found that more than 80 species traveled thousands of kilometers aboard pumice following the 2006 eruption of Home Reef Volcano in Tonga. “Pumice is an extremely effective rafting agent that can…connect isolated shallow marine and coastal ecosystems,” the researchers wrote in PLoS ONE.

The long-distance journeys of pumice rafts are “definitely a way to get organisms to disperse widely,” said Erik Klemetti, a volcanologist at Denison University in Granville, Ohio, not involved in the research. But the idea that the stowaways aboard pumice rafts might replenish the Great Barrier Reef’s corals is wishful thinking, said Klemetti. “That’s probably an oversell.”

Jutzeler and his colleagues are planning to study pumice from last month’s eruption. They’ve been in touch with several vessels that passed through the rafts, and they’ve arranged to analyze some of the rocks. (But the samples they’ve been promised are currently stuck in transit in Fiji, said Jutzeler.)

By analyzing the chemistry of the pumice, Jutzeler and his colleagues hope to learn about the properties of the underwater volcanic eruption. For instance, was it eruptive or effusive?

Studying the rocks’ surfaces will also reveal how quickly they’re being abraded, which will shed light on how rapidly volcanic dust is being deposited into the ocean. That’s important because some plankton feed on this volcanic debris, which can result in phytoplankton blooms, said Jutzeler.

Jutzeler and other researchers are keeping a close watch on how the rafts are moving. Satellite imagery—from Terra, Aqua, Sentinel, and Landsat satellites, for instance—provides nearly daily updates. Ocean currents, wind, and waves sculpt and power the rafts, which now number in the hundreds.

NASA Terra satellite

ESA Sentinels (Copernicus)

NASA/Landsat 8

They’ll likely arrive in Fiji in a few weeks, Jutzeler predicts.

See the full article here .

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Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

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From The New York Times: “We’re Barely Listening to the U.S.’s Most Dangerous Volcanoes”

New York Times

From The New York Times

Sept. 9, 2019
Shannon Hall

A thicket of red tape and regulations have made it difficult for volcanologists to build monitoring stations along Mount Hood and other active volcanoes.

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Mount Hood in Oregon is one of 161 active volcanoes in the United States, many of them in the Pacific Northwest’s Cascade Range.Credit Amanda Lucier for The New York Times

Seth Moran is worried about Mount Hood.

In the 1780s, the volcano rumbled to life with such force that it sent high-speed avalanches of hot rock, gas and ash down its slopes. Those flows quickly melted the snow and ice and mixed with the meltwater to create violent slurries as thick as concrete that traveled huge distances. They destroyed everything in their path.

Today, the volcano, a prominent backdrop against Portland, Ore., is eerily silent. But it won’t stay that way.

Mount Hood remains an active volcano — meaning that it will erupt again. And when it does, it could unleash mudflows not unlike those from Colombia’s Nevado del Ruiz volcano in 1985. There, a mudflow entombed the town of Armero, killing roughly 21,000 people in the dead of night.

On Mount Hood, “any little thing that happens could have a big consequence,” said Dr. Moran, scientist-in-charge at the federal Cascades Volcano Observatory.

And yet the volcano is hardly monitored. If scientists miss early warning signs of an eruption, they might not know the volcano is about to blow until it’s too late.

Determined to avoid such a tragedy, Dr. Moran and his colleagues proposed installing new instruments on the flanks of Mount Hood in 2014. Those include three seismometers to measure earthquakes, three GPS instruments to chart ground deformation and one instrument to monitor gas emissions at four different locations on the mountain.

But they quickly hit a major hiccup: The monitoring sites are in wilderness areas, meaning that the use of the land is tightly restricted. It took five years before the Forest Service granted the team approval in August.

The approval is a promising step forward, but Dr. Moran and his colleagues still face limitations, including potential legal action that may block their work.

Such obstacles are a problem across the United States where most volcanoes lack adequate monitoring. Although federal legislation passed in March could help improve the monitoring of volcanoes like Mount Hood, scientists remain concerned that red tape could continue to leave them blind to future eruptions, with deadly consequences.

Listening for rumbles and belches

The United States is home to 161 active volcanoes, many of which form a line along the west coast through California, Oregon, Washington and Alaska. Seven of the 10 most dangerous American volcanoes are within the Cascade Range, and six of those are not adequately monitored.

In contrast, countries like Japan, Iceland and Chile smother their high-threat volcanoes in scientific instruments.

“The U.S. really doesn’t have anything to this level,” said Erik Klemetti, a volcanologist at Denison University in Ohio.

Yet there is no question that better monitoring could save lives. Volcanoes don’t typically erupt without warning. As Mount St. Helens awoke in May 1980, a series of small earthquakes could be felt on the surface nearby. Shortly thereafter, the volcano started to deform. Steam explosions sculpted a new crater, while a bulge emerged on the volcano’s north flank. Earthquakes continued, landslides rumbled and ash-rich plumes erupted — all before the main event.

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Mount St. Helens awoke in May 1980. OregonLive.com

Although not all volcanoes follow such a steady, pre-eruptive pattern, they typically either tremble, deform or belch volcanic gases — meaning that if scientists monitor these three signals, they will likely be able to forecast when a volcanic eruption will happen.

Take Hawaii as an example. Shortly after earthquakes picked up at the Kilauea volcano on April 30, 2018, scientists at the Hawaiian Volcano Observatory could tell that they were not only increasing, but they were also propagating to the east.

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Kilauea volcano on April 30, 2018. Lava flowing on May 6 through the Leilani Estates subdivision. Credit Bruce Omori/EPA, via Shutterstock.

“That was not only cool, it was vital for emergency management,” Dr. Moran said.

Scientists used those signals to project where magma might erupt, and planners evacuated residents in that area. The eruption destroyed more than 700 homes, but remarkably no one died.

And it was all thanks to 60 seismic stations located across the island.

“Without those instruments, we would have been blind,” said Tina Neal, the scientist-in-charge at the Hawaiian Volcano Observatory. “While we would have known something was happening, we would have been less able to give guidance about where and what was likely to happen.”

Nature’s Bill of Rights

Dr. Moran and his colleagues had that example in mind as they pressed their case for adding instruments to Mount Hood.

They submitted a proposal to the Forest Service in 2014. But the instruments — which will be housed in four-feet-tall boxes with radio antennas and solar panels on the outside — violate the Wilderness Act, which prohibits any new structures and even noise pollution within federal wilderness areas.

“I see the Wilderness Act as nature’s bill of rights,” said George Nickas, the executive director of Wilderness Watch, a conservation group that opposed volcano monitoring in federal wilderness. “I think it is so important to have places like that where we can just step back, out of respect and humility, and appreciate nature for what it is.”

In reviewing Dr. Moran’s proposal, the Forest Service provided the public with an opportunity to comment, during which they received more than 2,000 statements — most of which agreed that the wilderness needs safeguarding.

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U.S.G.S. volcano monitoring equipment, right, on Mount St. Helens. Credit Amanda Lucier for The New York Times.

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Fiberglass enclosures for volcano monitoring equipment awaiting placement on Mount Hood. Credit Amanda Lucier for The New York Times.

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When Mount St. Helens first began to rumble, scientists couldn’t tell if the quakes originated under the volcano itself or at a nearby fault. Scientists rushed to place additional instruments and within days they knew the volcano itself was shaking. Credit Amanda Lucier for The New York Times.

To Jonathan Fink, a geologist at Portland State University who also wrote a public comment in favor of volcano monitoring, this argument is misplaced.

“I’m all for protecting wilderness,” Dr. Fink said. “But this is just a question of public safety. And I think letting a helicopter in to put some instruments in that can then be monitored remotely seems like a pretty minor exception to the wilderness policies.”

Even so, many critics argue that we can’t make even a single exception — or there won’t be wilderness at all.

“It’s not wilderness if you have structures, if you have roads, if you have motorization,” said Gary Macfarlane, Wilderness Watch’s president. “In fact, it’s antithetical to the whole idea of wilderness.”

Lessons from Mount St. Helens

Other critics say the project is far from necessary. “If we can do something like land one of those landers on Mars, we can move a few miles back from a volcanic feature and monitor it from a little further away,” said Bernie Smith, a retired employee of the Forest Service who wrote a public comment against the project.

But Dr. Moran and others argue that the work is not possible unless they get up close, and before the volcano begins to rock.

“The name of the game is to be able to detect and correctly interpret these warning signs as soon as possible — to give society as much time as possible to get ready,” Dr. Moran said.

When Mount St. Helens first began to rumble, scientists couldn’t tell if the quakes originated under the volcano itself or five miles away at a nearby fault. They only had one seismometer two miles to the west of the volcano. So they rushed to place more instruments on its slopes (a risk that would not be allowed today) and within days they knew the volcano itself was shaking.

“Looking back on it, it’s really miraculous that they were able to do what they did,” Dr. Moran said.

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The Calbuco volcano erupting in southern Chile on April 22, 2015. Credit Diego Main/Agence France-Presse — Getty Images

Scientists have since learned that we don’t always get as much time as Mount St. Helens allowed. At Calbuco, a volcano in southern Chile that’s similar to the volcanoes in the Cascades, all was quiet during the early afternoon of April 22, 2015. But tremors began in the late afternoon, and by 6:04 p.m. local time, the mountain was sending a plume of gas 10 miles into the sky.

With such a narrow window, the first line of defense is to have a solid monitoring network in place whenever a volcano awakens.

“You’re going to either get in there ahead of time and put in the instrumentation you need, or you’re just going to accept that you’re going to go blind into the entire eruptive period and whatever happens, happens,” said Jacob Lowenstern, a geologist with the United States Geological Survey.

Not if, but when

Although none of these volcanoes appear to be building toward an eruption today, there is no question that they pose a serious hazard.

“The U.S.G.S. has a deep understanding that these volcanoes are going to erupt again — within our lifetimes, our children’s lifetimes,” said Carolyn Driedger, a hydrologist at the Cascades observatory. “The evidence is all there.”

Beyond Mount Hood, Mount Rainier near Seattle could also unleash viscous volcanic mudflows. There, 80,000 people live in the path of disaster and yet the mountain only has 19 instruments, which scientists say is not enough given its vast size.

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Aerial photo of Mount Rainier from the west. Stan Shebs

And even volcanoes that don’t loom so close to populated areas could have far-reaching effects.

Glacier Peak in northern Washington has produced some of the most explosive eruptions in the contiguous United States, meaning the ability to throw enough ash into the air to halt air traffic for days or even weeks and cost billions of dollars. It has only one seismometer.

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Glacier Peak. Walter Siegmund

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Andy Lockhart, a geophysicist at the Cascades observatory, working on a tripwire for part of a system to detect debris flow to be placed on Mount Rainier. Credit Amanda Lucier for The New York Times.

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Seismometers at the Cascades Volcano Observatory awaiting placement on Mount Hood. Credit Amanda Lucier for The New York Times.

Without equipment to detect the eruption, airplane passengers just might find themselves living a high-altitude nightmare. In 1989, a Boeing 747 flew through an undetected ash cloud in Alaska. All four engines shut down and the airplane went into a nose-dive. It descended 13,000 feet before the pilots were able to restart the engines. Hundreds of thousands of people fly across the West Coast and above active volcanoes every day.

Eruptions in Alaska and California would also be felt across the nation. Anchorage is a major cargo hub, meaning that many FedEx or U.P.S. packages travel through Alaska. But an eruption might bring that to an alarming halt. And because California produces a large portion of the nation’s food, an eruption might limit the fruits and vegetables found at supermarkets as far as the East Coast.

“We’re not just doing this for academic purposes. This is so we can give good information to emergency managers,” Dr. Driedger said. “That’s the end in all of this.”

Hoping for slumber

Despite the permit’s recent approval, Dr. Driedger notes that there are still a number of steps before any instruments can be placed on Mount Hood. They will now have to choreograph the assembly of instruments, hire personnel and schedule helicopter trips around weather and other potential obstacles.

Moreover, the Forest Service and the observatory could still face a legal challenge from Wilderness Watch or other groups that adds years to the installation, if not blocking it altogether.

“This is more proof that the Forest Service has abandoned any pretense of administering wilderness as per the letter or spirit of the Wilderness Act,” said Mr. Macfarlane, whose group is discussing litigation with an attorney but has not yet decided whether to file suit.

And then there is more work to be done monitoring other hazardous volcanoes beyond Mount Hood.

Volcanologists across the nation were pleased this March when Congress passed the National Volcano Early Warning and Monitoring System Act, which seeks to ensure that volcanoes nationwide are adequately monitored.

But the bill is only an authorization — meaning that Congress has not actually invested the $55 million over five years required to apply for new permits, install more equipment and pay to monitor 34 of the nation’s most dangerous volcanoes. Nor will it change the fact that scientists like Dr. Moran must still grapple with regulations protecting federal wilderness.

So Dr. Moran, aware that litigation is a possibility, is moving forward with caution. This month, his team will begin to install monitoring stations at Mount Hood. He then hopes the Forest Service will issue a permit to install equipment at Glacier Peak, then turn back to Washington’s Mount Baker. Eventually he would like to install more instruments on Mount Hood, but first he needs to create sufficient networks elsewhere.

While they wait, Dr. Moran and his colleagues will hold their breath, hopeful that these volcanoes stay in a deep slumber, but aware that one just might rouse at any moment.

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Location is not identified. Amanda Lucier for The New York Times.

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From Brown University: “Research shows why there’s a ‘sweet spot’ depth for underground magma chambers”

Brown University
From Brown University

Computer models show why eruptive magma chambers tend to reside between six and 10 kilometers underground.

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A new study reveals why the magma chambers that feed recurrent and often explosive volcanic eruptions tend to reside in a very narrow depth range within the Earth’s crust. The findings, published in Nature Geoscience, could help scientists to better understand volcanic processes the world over.

The research makes use of computer models that capture the physics of how magma chambers, reservoirs in the crust that contain partially molten rock, evolve over time. The models showed that two factors — the ability of water vapor to bubble out of the magma, and the ability of the crust to expand to accommodate chamber growth — are the key factors constraining the depth of magma chambers, which are generally found between six and 10 kilometers deep.

“We know from observations that there seems to be a sweet spot in terms of depth for magma chambers that erupt repeatedly,” said Christian Huber, a geologist at Brown University and the study’s lead author. “Why that sweet spot exists has been an open question for a long time, and this is the first study that explains the processes that control it.”

Depths of six to 10 kilometers generally correspond to pressures of about 1.5 kilobars on the shallow side and 2.5 kilobars on deep side. The models showed that at pressures less than 1.5 kilobars, water trapped within the magma forms bubbles readily, leading to violent volcanic explosions that blast more magma out of a chamber than can be replaced. These chambers quickly cease to exist. At pressures more than 2.5 kilobars, warm temperatures deep inside the Earth make the rocks surrounding the magma chamber soft and pliable, which enables the chamber to grow comfortably without erupting to the surface. These systems cool and solidify over time without ever erupting.

“Between 1.5 and 2.5, the systems are happy,” Huber said. “They can erupt, recharge and keep going.”

The key to the models, Huber said, is that they capture the dynamics of both the host crust and of the magma in the chamber itself. The ability of deep magma chamber to grow without erupting was fairly well understood, but the limit that water vapor exerts on shallow magma chambers hadn’t been appreciated.

“There hadn’t been a good explanation for why this habitable zone should end at 1.5 kilobars,” Huber said. “We show that the behavior of the gas is really important. It simply causes more mass to erupt out than can be recharged.”

Huber says the findings will be helpful in understanding the global magma budget.

“The ratio of magma that stays in the crust versus how much is erupted to the surface is a huge question,” Huber said. “Magma supplies CO2 and other gases to the atmosphere, which influences the climate. So having a guide to understand what comes out and what stays in is important.”

Coauthors on the paper Meredith Townsend, WimDegruyter and Olivier Bachmann. The work was supported by the National Science Foundation (NSF-EAR 1760004) and the Swiss National Fund (200021_178928).

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With its talented and motivated student body and accomplished faculty, Brown is a leading research university that maintains a particular commitment to exceptional undergraduate instruction.

Brown’s vibrant, diverse community consists of 6,000 undergraduates, 2,000 graduate students, 400 medical school students, more than 5,000 summer, visiting and online students, and nearly 700 faculty members. Brown students come from all 50 states and more than 100 countries.

Undergraduates pursue bachelor’s degrees in more than 70 concentrations, ranging from Egyptology to cognitive neuroscience. Anything’s possible at Brown—the university’s commitment to undergraduate freedom means students must take responsibility as architects of their courses of study.

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From Rice University: “The ‘universal break-up criterion’ of hot, flowing lava”

Rice U bloc

From Rice University

August 30, 2019
Jade Boyd

Tool lets scientists examine changing behavior of low-viscosity lava.

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Thomas Jones is a Rice Academy Postdoctoral Fellow in Rice University’s Department of Earth, Environmental and Planetary Sciences. (Photo courtesy of T. Jones)

Thomas Jones’ “universal break-up criterion” won’t help with meltdowns of the heart, but it will help volcanologists study changing lava conditions in common volcanic eruptions.

Jones, of Rice University, studies the behavior of low-viscosity lava, the runny kind that’s found at most volcanoes. About two years ago, he began a series of lab experiments and field observations that provided the raw inputs for a new fluid dynamic model of lava break-up. The work is described in a paper in Nature Communications.

Low-viscosity lava is the red-hot, flowing type one might see at Hawaii’s famed Kilauea volcano, and Jones said it usually behaves in one of two ways.

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Lava fountains at Kilauea in Hawaii created a spatter cone, which was estimated to be 180 feet tall in this June 2018 photo. (Image courtesy of U.S. Geological Survey)

“It can bubble or spew out, breaking into chunks that spatter about the vent, or it can flow smoothly, forming lava streams that can rapidly move downhill,” he said.

But that behavior can sometimes change quickly during the course of an eruption, and so can the associated dangers: While spattering eruptions throw hot lava fragments into the air, lava flows can threaten to destroy whole neighborhoods and towns.

Jones’ model, the first of its kind, allows scientists to calculate when an eruption will transition from a spattering spray to a flowing stream, based upon the liquid properties of the lava itself and the eruption conditions at the vent.

Jones said additional work is needed to refine the tool, and he looks forward to doing some of it himself.

“We will validate this by going to an active volcano, taking some high-speed videos and seeing when things break apart and under what conditions,” he said. “We also plan to look at the effect of adding bubbles and crystals, because real magmas aren’t as simple as the idealized liquid in our mathematical model. Real magmas can also have bubbles and crystals in them. I’m sure those will change things. We want to find out how.”

Jones said pairing the new model with real-time information about a lava’s liquid properties and eruption conditions could allow emergency officials to predict when an eruption will change style and become a hazard to at-risk communities.

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Lava from a fountain on Hawaii’s Kilauea volcano flows over a spillway into an established channel in June 2018. (Image courtesy of U.S. Geological Survey)

“We want to use this as a forecasting tool for eruption behavior,” he said. “By developing a model of what’s happening in the subsurface we can then watch for indications that it’s about to cross the tipping point and change behavior.”

The study was co-authored by C.D. Reynolds of the University of Birmingham in the United Kingdom and S.C. Boothroyd of Durham University, also in the UK. The research was supported by the UK’s National Environment Research Council and Rice University.

See the full article here .


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Stem Education Coalition

Rice U campus

In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

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From University of Aberdeen: “Jurassic world of volcanoes found in central Australia”

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From University of Aberdeen

13 August 2019

An international team of subsurface explorers from the University of Aberdeen and University of Adelaide have discovered a ‘Jurassic World’ of around 100 ancient volcanoes buried deep beneath Australia’s largest onshore oil and gas producing region.

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The volcanoes developed between 180 and 160 million years ago, and have been buried beneath hundreds of meters of sedimentary – or layered – rocks.

The Cooper-Eromanga Basins – a dry and barren landscape located in the north-eastern corner of South Australia and south-western corner of Queensland – has seen about 60 years of petroleum exploration and production, however this ancient Jurassic volcanic underground landscape has gone largely unnoticed.

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Cooper/ Eromanga Basin. Blue Energy

The volcanoes developed in the Jurassic period, between 180 and 160 million years ago, and have been subsequently buried beneath hundreds of meters of sedimentary – or layered – rocks.

Published in the journal Gondwana Research, the researchers used advanced subsurface imaging techniques, analogous to medical CT scanning, to identify the plethora of volcanic craters and lava flows, and the deeper magma chambers that fed them.

They’ve called the volcanic region the Warnie Volcanic Province, with a nod to Australian cricket legend Shane Warne.

In Jurassic times, the researchers say, the area would have been a landscape of craters and fissures, spewing hot ash and lava into the air, and surrounded by networks of river channels, evolving into large lakes and coal-swamps.

“While the majority of Earth’s volcanic activity occurs at the boundaries of tectonic plates, or under the Earth’s oceans, this ancient Jurassic world developed deep within the interior of the Australian continent,” said co-author Associate Professor Simon Holford, from the University of Adelaide’s Australian School of Petroleum.

“Its discovery raises the prospect that more undiscovered volcanic worlds reside beneath the poorly explored surface of Australia.”

The research was carried out by Jonathon Hardman, then a PhD student at the University of Aberdeen, as part of the Natural Environment Research Council Centre for Doctoral Training in Oil and Gas.

The researchers say that Jurassic-aged sedimentary rocks bearing oil, gas and water have been economically important for Australia, but this latest discovery suggests a lot more volcanic activity in the Jurassic period than previously supposed.

“The Cooper-Eromanga Basins have been substantially explored since the first gas discovery in 1963,” said co-author Associate Professor Nick Schofield, from the University of Aberdeen’s Department of Geology and Petroleum Geology.

“This has led to a massive amount of available data from underneath the ground but the volcanics have never been properly understood in this region until now. It changes how we understand processes that have operated in Earth’s past.”

The researchers have named their discovery the Warnie Volcanic Province after one of the drill holes that penetrated Jurassic volcanic rocks (Warnie East-1, itself named after a nearby waterhole), but also in recognition of the explosive talent of former Australian cricketer Shane Warne.

“We wrote much of the paper during a visit to Adelaide by the Aberdeen researchers, when a fair chunk was discussed and written at Adelaide Oval during an England vs Cricket Australia XI match in November 2017,” explained Associate Professor Holford.

“Inspired by the cricket, we thought Warnie a good name for this once fiery region.”

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

U Aberdeen Campus

Founded in 1495 by William Elphinstone, Bishop of Aberdeen and Chancellor of Scotland, the University of Aberdeen is Scotland’s third oldest and the UK’s fifth oldest university.

William Elphinstone established King’s College to train doctors, teachers and clergy for the communities of northern Scotland, and lawyers and administrators to serve the Scottish Crown. Much of the King’s College still remains today, as do the traditions which the Bishop began.

King’s College opened with 36 staff and students, and embraced all the known branches of learning: arts, theology, canon and civil law. In 1497 it was first in the English-speaking world to create a chair of medicine. Elphinstone’s college looked outward to Europe and beyond, taking the great European universities of Paris and Bologna as its model.
Uniting the Rivals

In 1593, a second, Post-Reformation University, was founded in the heart of the New Town of Aberdeen by George Keith, fourth Earl Marischal. King’s College and Marischal College were united to form the modern University of Aberdeen in 1860. At first, arts and divinity were taught at King’s and law and medicine at Marischal. A separate science faculty – also at Marischal – was established in 1892. All faculties were opened to women in 1892, and in 1894 the first 20 matriculated female students began their studies. Four women graduated in arts in 1898, and by the following year, women made up a quarter of the faculty.

Into our Sixth Century

Throughout the 20th century Aberdeen has consistently increased student recruitment, which now stands at 14,000. In recent years picturesque and historic Old Aberdeen, home of Bishop Elphinstone’s original foundation, has again become the main campus site.

The University has also invested heavily in medical research, where time and again University staff have demonstrated their skills as world leaders in their field. The Institute of Medical Sciences, completed in 2002, was designed to provide state-of-the-art facilities for medical researchers and their students. This was followed in 2007 by the Health Sciences Building. The Foresterhill campus is now one of Europe’s major biomedical research centres. The Suttie Centre for Teaching and Learning in Healthcare, a £20m healthcare training facility, opened in 2009.

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