BREAKING NEWS: Mantle Plumes Source of Mid-Ocean Ridges

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Two-thirds of Earth’s surface is covered in oceanic crust, but the deep plumbing that generates new crust remains poorly understood. New images from a chain of volcanoes beneath the Pacific Ocean show that magma may be erupting from a multi-layered magma chamber extending two miles or more…

Two-thirds of Earth’s surface is covered in oceanic crust, but the deep plumbing that generates new crust remains poorly understood. New images from a chain of volcanoes beneath the Pacific Ocean show that magma may be erupting from a multi-layered magma chamber extending two miles or more beneath the seafloor, far deeper than originally thought.

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Photos just published in the scientific journal Nature Geoscience, may help resolve a debate about how new crust forms at mid-ocean ridges where Earth’s tectonic plates are slowly pulling apart. In one hypothesis, the lower crust is formed as a shallow pool of magma beneath the volcanic spreading center solidifies, forming a kind of crystalline glacier that oozes down and out.

“We now see that during an eruption we may have magma moving from one level to another,” said study coauthor Suzanne Carbotte, a geophysicist at Columbia University’s Lamont-Doherty Earth Observatory.

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In another view, pools of magma stacked vertically form new rocks at depths throughout the crust, and send lava to Earth’s surface, creating the upper and lower crust in one fell swoop.  The new images seem to support the multi-tier view, predicted by geologists who have studied eroded oceanic crust on land.

The pictures come from a 2008 research expedition to the East Pacific Rise, a chain of submarine volcanoes that run from California’s Salton Sea to the northern shores of Antarctica. Aboard the R/V Langseth, the scientists used pulses of sound to map the sub-seafloor beneath a region that saw massive eruptions from 2005 to 2006.

In the sub-surface images, Carbotte and former Lamont graduate student Milena Marjanovic and others on the cruise recognized multi-layered magma pools, or “melt lenses,” stacked one on top of the other. In addition, these multiple tiers looked as if they had been connected during the eruption.

A multi-tier magma chamber had been predicted in 1998 by Lamont-Doherty geophysicist Peter Kelemen and colleagues based on field observations in the Middle Eastern nation of Oman, where mantle peridotites formerly at the bottom of the ocean have been heaved onto land, providing easy access. Kelemen and colleagues discovered that rocks in close proximity had different chemical signatures. That would be impossible if a slow-oozing crystalline mush had created them. To Kelemen, Oman’s uneven but undeformed rock layers, too, seemed inconsistent with such a model.

“We could identify some bodies of rock that surely had formed in deeper melt lenses within the uppermost mantle, and we showed that they were very similar to the rocks throughout the crust,” said Kelemen, who was not involved in the Nature Geoscience study.

“We hoped that someday techniques would improve and the deeper lenses would emerge from their obscurity,” he added. “With the dedication and hard work of many research teams, this finally seems to be happening.”

Scientists are using volcanic gases to understand how volcanoes work, and as the basis of a hazard-warning forecast system.

When the USA’s Mount St Helens erupted in 1980, just two months after showing signs of reawakening, its blast was equivalent to 1,600 times the energy of the atomic bomb dropped on Hiroshima. It remains the most economically destructive volcanic event in the USA’s history.

When Eyjafjallajӧkull erupted in 2010 in Iceland, the ash cloud it emitted stranded around half of the world’s air traffic, with an estimated global economic cost of US $5 billion. Recently, magma has been on the move again, this time under and beyond Iceland’s Bárðarbunga volcano.

Volcanoes are the vents through which our planet exhales. Yet, not all volcanoes experience spectacular releases of energy, or even erupt at all: of the 500 or so volcanoes that are currently active worldwide, 20 might be expected to erupt in any one year. But, when volcanoes do erupt, they can cause almost total destruction in the immediate vicinity and the ash clouds they release can affect areas thousands of kilometers away.

Fortunately, the ability to monitor volcanoes has dramatically improved in recent years, thanks in part to the work of scientists like Dr Marie Edmonds in Cambridge’s Department of Earth Sciences.

Studying the behavior of volcanoes such as Soufrière Hills in Montserrat, which caused the displacement of two-thirds of the island’s population (over 8,000 people) when it erupted in 1995, Edmonds and colleagues have accumulated huge datasets on everything from the type and quantity of gas belched from volcanoes, to the bulging and deformation of the volcanoes’ shape, to the altitude and quantity of ash thrown up into the stratosphere.

“About 600 million people live close enough to an active volcano to have their lives disturbed or threatened, so there’s a clear need for hazard assessment,” Edmonds said. “We knew that gas monitoring data could be essential for this, but monitoring depended on the use of cumbersome instruments that had to be driven around the crater’s edge.”

In the early 2000s, with funding from the Natural Environment Research Council (NERC), she and Dr Clive Oppenheimer from the Department of Geography developed a new gas sensor – one that is cheap, miniaturized and can be left long term on the volcano, relaying the data back to the observatory by radio modem. Today, sensors like these are used by scientists worldwide for monitoring volcanoes.

“Previous studies had shown that changes in the emission rate of gases correlated with volcanic activity but, because we have such a long dataset, we began to see another pattern emerging,” said Edmonds. “What you see at the volcano surface is really only the end part of the story.”

The intense temperatures and pressures deep in the earth find release through fissures and cracks, which carry dissolved gases such as carbon dioxide (CO2), sulphur dioxide (SO2), hydrogen chloride (HCl) and steam up through the mantle to the crust.

As the magma begins its journey to the surface, the pressure lowers and dissolved gases form tiny bubbles, which start to expand. Close to the surface, the expansion can be so great that it fuels an explosive burst of lava, shooting volcanic gases tens of kilometers into the earth’s atmosphere.

Because each species of gas dissolves at different pressures, the scientists can measure what is released at the surface and use this to work out the depth at which the gases separated from the magma to form bubbles. “The gases are like messages that tell you how the volcano is ‘plumbed’ and what shape that plumbing is in,” explained Edmonds.

“One intriguing pattern to emerge in Soufrière Hills is that the time series for the magma eruption and that for the SO2 gas eruption are completely unrelated to one another. There have been three big episodes of lava extrusion in the past 15 years and, although HCl flux seems to be a proxy for eruption rate, SO2 emission is uncoupled from what is happening in the eruption. We think the SO2 flux is telling us about something much deeper in the system.”

When these results were combined with a study of the rocks spewed from the volcano, Edmonds and colleagues began to piece together an idea of the physics and chemistry happening within.

They believe that a hot magnesium- and iron-rich ‘mafic’ magma is intruding from depth into the shallower magma chamber where it meets a silica- and crystal-rich ‘andesite’ magma that forms the main part of the eruption. However, it is the gas-rich mafic magma that Edmonds and colleagues believe triggers and fuels the eruption, and it is this that surface SO2 levels are a proxy for.

“This is far from the traditional view of how a magma chamber works,” said Edmonds. “It was thought to be balloon-like but now we think it’s vertically protracted, with different types of magma at different levels.”

“The surface SO2 is telling us about long-scale processes, of the order of months to years,” explained Edmonds. “Even though there may be no evidence of lava at the summit, if SO2 is still outgassing then there’s potential for the eruption to resume. We can to an extent use it to forecast a volcanic eruption.”

Recently, Edmonds and colleagues joined forces with researchers at other universities to understand how best to monitor volcanoes and earthquakes in two new NERC-funded projects. The £2.8 million Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET+) program run by the University of Leeds will provide new understanding of geohazards to underpin national risk capabilities; and the £3.7 million RiftVolc project will create a long-range eruptive forecast for the largely uncharted volcanoes in the East African Rift Valley.

For Soufrière Hills, monitoring is providing a key input to the risk assessments by the UK government’s Scientific Advisory Committee for Montserrat, a British Overseas Territory. “All the surface signs indicate the volcanic activity is decaying away but, from the SO2 emissions, the volcano remains active at depth. We think there’s a huge magma reservoir – tens of cubic kilometers beneath the island, much bigger than the island itself. We know from looking at older ash deposits on the island that this volcano is capable of much larger eruptions than we have seen in recent years, perhaps even as large as the Mount St Helens blast.”

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JUST IN: Colossal Volcanic Eruption Could Destroy Japan

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Japan could be nearly destroyed by a massive volcanic eruption over the next century, putting almost all of the country’s 127 million-strong population at risk, according to a new study.

“It is not an overstatement to say that a colossal volcanic eruption would leave Japan extinct…

Japan could be nearly destroyed by a massive volcanic eruption over the next century, putting almost all of the country’s 127 million-strong population at risk, according to a new study.

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“It is not an overstatement to say that a colossal volcanic eruption would leave Japan extinct as a country,” Kobe University Earth sciences professor Yoshiyuki Tatsumi and associate professor Keiko Suzuki said in a study publicly released on Wednesday.

The experts said they analyzed the scale and frequency of volcanic eruptions in the archipelago nation over the past 120,000 years and calculated that the odds of a devastating eruption at about one percent over the next 100 years.

The chance of a major Earthquake striking the city of Kobe within 30 years was estimated at about one percent just a day before a 7.2-magnitude quake destroyed the Japanese port city in 1995, killing 6,400 people and injuring nearly 4,400 others, the study noted.

“Therefore, it would be no surprise if such a colossal eruption occurs at any moment,” it added.

The new research comes weeks after Japan’s Mount Ontake erupted without warning—killing 57 people and leaving at least six others missing in the country’s deadliest volcanic eruption in almost 90 years.

The Kobe University researchers said their study was critical because Japan is home to about seven percent of the volcanoes that have erupted over the past 10,000 years.

A disaster on the southernmost main island of Kyushu, which has been struck by seven massive eruptions over the past 120,000 years, would see an area with seven million people buried by flows of lava and molten rock in just two hours, they said.

Volcanic ash would also be carried by westerly winds toward the main island of Honshu, making almost all of the country “unliveable” as it strangled infrastructure, including key transport systems, they said.

It would be “hopeless” trying to save about 120 million living in major cities and towns across Honshu, the study said.

This prediction was based on geological findings from the eruption of a gigantic crater, 23 kilometers (14 miles) across, in southern Kyushu about 28,000 years ago.

The study called for new technology to accurately grasp the state of “magma reservoirs” which are spread across the Earth’s crust in layers a few kilometers deep.

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BREAKING NEWS: Sun Ramps Up with X and M-class Flares

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During the past 24 hours, sunspot region 2192 produced an X1.6 flare and four M-class flares – all of which are Earth directed. There are no CMEs associated with this activity. Region 2192 is currently situated at the solar central meridian – a major eruption in this active region…

During the past 24 hours, sunspot region 2192 produced an X1.6 flare and four M-class flares – all of which are Earth directed. There are no CMEs associated with this activity. Region 2192 is currently situated at the solar central meridian – a major eruption in this active region may lead to a geo-effective CME (coronal mass ejection) and a proton event.

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Additionally, sunspot region 2195 produced an M1.4 flare peaking at 15:57 UT, and this flare was associated only with a narrow CME. Region 2192 will remain the main flare source as it continues to grow and maintains the beta-gamma-delta configuration.

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The Earth is currently inside a slow (around 430 km/s) solar wind flow with average (around 5 nT) interplanetary magnetic field (IMF) magnitude. The geomagnetic conditions are quiet and are expected to remain so.

Note: Sunspot region 2192 is large enough to be seen with the naked eye during this solar eclipse.

Yesterday an interval of K = 5 was reported by IZMIRAN and an interval of K = 4 by Dourbes (K index according to NOAA remained at the quiet to unsettled levels with K < 4). This interval of slightly disturbed geomagnetic conditions was produced by a slow solar wind interval with predominantly negative north-south IMF component Bz.

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Philippines’ Mayon Volcano: Risk of ‘Imminent Eruption’ as Lava Flows and Earthquakes Shake Region

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An eruption at the Mayon volcano in the Philippines could be imminent, with a second lava flow spotted as dozens of tremors have shaken the region.
An aerial survey taken of Mayon, situated in the province of Albay, showed the volcano is still showing signs of increased seismic activity although…

An eruption at the Mayon volcano in the Philippines could be imminent, with a second lava flow spotted as dozens of tremors have shaken the region.

An aerial survey taken of Mayon, situated in the province of Albay, showed the volcano is still showing signs of increased seismic activity although the lava flow has stopped.

A volcanologist at the Philippine Institute of Volcanology and Seismology (Phivolcs), Eduardo Laguerta, said: “The lava flow could be an indication of an imminent eruption, just like in 1984, when after the lava flow had been spotted, within two weeks the volcano erupted.”

This is the second lava flow to be observed from Mayon in two weeks. The first was seen on 12 October, the first since Mayon started showing activity in mid-September.

In 1984, more than 73,000 people were evacuated from the danger zones as recommended by scientists. Over 54,000 individuals have been evacuated within the six-km permanent danger zone so far.

On Monday night, the alert level was raised to a three, suggesting magma is at the crater of the volcano and a hazardous eruption is possible within weeks.

The Most Active Volcano in the Philippines

Phivolcs told GMA News it had observed a moderate emission of white steam plumes drifting from the volcano. It also noted a faint crater glow from the centre of the dome, measuring the new lava flow to be between 300m and 400m long.

The institute said this indicates Mayon is in a “state of unrest” due to the movement of “potentially eruptible magma”.

In the last 24 hours, Phivolcs has recorded 45 volcanic earthquakes and 270 rockfall events.

Rolling rockfall within the uppermost reaches of the Bonga Gully indicates that the summit lava dome is breaching the crater in its southeastern side.

“It’s already erupting, but not explosive,” said Renato Solidum, Phivolcs executive director. “Currently, the activity is just lava coming down. If there is an explosion, all sides of the volcano are threatened.”

New ash deposits have been spotted at the slopes of Mayon and last week, sulfur dioxide emission was recorded at 272 tons a day.

Mount Mayon, a popular tourist site known for its near-perfect cone, is considered as the most active volcano in the Philippines. It has erupted 50 times in the last 500 years, sometimes violently.

In May 2013, the volcano suddenly released ash which killed five climbers who had ventured near the summit despite danger warnings.

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Researchers Find Evidence Of Earth’s Formation Trapped In Samoan Volcano

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Researchers have found an unusual glimpse of the beginning of Earth deep in a Samoan volcano.
Known as hotspots, volcanic island chains such as Samoa can have ancient primordial signatures from the early solar system that have somehow survived billions of years.
Researchers now say they have…

Researchers have found an unusual glimpse of the beginning of Earth deep in a Samoan volcano.

Known as hotspots, volcanic island chains such as Samoa can have ancient primordial signatures from the early solar system that have somehow survived billions of years.

Researchers now say they have found unique chemical signatures that show them what conditions were like.

The UC Santa Barbara geochemist studying Samoan volcanoes has found evidence of the planet’s early formation still trapped inside the Earth.

Matthew Jackson, an associate professor in UCSB’s Department of Earth Science, and colleagues utilized high-precision lead and helium isotope measurements to unravel the chemical composition and geometry of the deep mantle plume feeding Samoa’s volcanoes.

Their findings appear today in the journal Nature.

In most cases, volcanoes are located at the point where two tectonic plates meet, and are created when those plates collide or diverge.

Hotspot volcanoes, however, are not located at plate boundaries but rather represent the anomalous melting in the interior of the plates.

Such intraplate volcanoes form above a plume-fed hotspot where the Earth’s mantle is melting.

The plate moves over time — at approximately the rate human fingernails grow (3 inches a year) — and eventually the volcano moves off the hotspot and becomes extinct.

Another volcano forms in its place over the hotspot and the process repeats itself until a string of volcanoes evolves.

‘So you end up with this linear trend of age-progressive volcanoes,’ Jackson said.

‘On the Pacific plate, the youngest is in the east and as you go to the west, the volcanoes are older and more deeply eroded.

Hawaii has two linear trends of volcanoes — most underwater — which are parallel to each other.

There’s a southern trend and a northern trend.’

Because the volcanic composition of parallel Hawaiian trends is fundamentally different, Jackson and his team decided to look for evidence of this in other hotspots.
In Samoa, they found three volcanic trends exhibiting three different chemical configurations as well as a fourth group of a late-stage eruption on top of the third trend of volcanoes.

These different groups exhibit distinct compositions.

‘Our goal was to figure out how we could use this distribution of volcano compositions at the surface to reverse-engineer how these components are distributed inside this upwelling mantle plume at depth,’ Jackson said.

Each of the four distinct geochemical compositions, or endmembers, that the scientists identified in Samoan lavas contained low Helium-3 (He-3) and Helium-4 (He-4) ratios.

The team said the surprising discovery was that they all exhibited evidence for mixing with a fifth, rare primordial component consisting of high levels of He-3 and He-4.

‘We have really strong evidence that the bulk of the plume is made of the high Helium-3, -4 component,’ Jackson said.

‘That tells us that most of this plume is primordial material and there are other materials hosted inside of this plume with low Helium-3, -4, and these are likely crustal materials sent into the mantle at ancient subduction zones.’

The unique isotopic topology revealed by the researchers’ analysis showed that the four low-helium endmembers do not mix efficiently with one another. However, each of them mixes with the high He-3 and He-4 component.

‘This unique set of mixing relationships requires a specific geometry for the four geochemical flavors within the upwelling plume: They must be hosted within a matrix that is composed of the rare fifth component with high He-3,’ Jackson explained.

‘This new constraint on plume structure has important implications for how deep mantle material is entrained in plumes, and it gives us the clearest picture yet for the chemical structure of an upwelling mantle plume.’

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Tropical Depression Forms Off Yucatan, Threatens South Florida With Heavy Rain

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A wet, messy storm in Mexico’s Bay of Campeche strengthened early Wednesday to a tropical depression, a warning that the Atlantic hurricane season is still open for business.
The system, a remnant of Tropical Storm Trudy that triggered fatal mudslides in southern Mexico last week, is expected to …

A wet, messy storm in Mexico’s Bay of Campeche strengthened early Wednesday to a tropical depression, a warning that the Atlantic hurricane season is still open for business.

The system, a remnant of Tropical Storm Trudy that triggered fatal mudslides in southern Mexico last week, is expected to become a tropical storm Wednesday as it heads toward the Yucatan Peninsula with winds of about 35 mph, the National Hurricane Center said. But forecasters expect a cold front moving south to keep it from growing as the storm nears the U.S. coast. Still, South Florida could get hit with heavy rain and possible flooding later this week.

Where and when the tropical storm’s remnants and the cold front collide will probably determine who gets soaked, said NHC spokesman Dennis Feltgen.

“They’re playing a game of what if and when,” Feltgen said.

As it crosses the Yucanta, the storm could produce five to 10 inches of rain and life-threatening floods, forecasters warned. A Hurricane Hunter plane was investigating the system Wednesday morning.

The crucial front, part of a nor’easter off the coast of New Jersey and New York, is expected to reach Lake Okeechobee by Wednesday evening, said National Weather Service meteorologist Barry Baxter. The front won’t bring dry air or cooler temperatures, but it could push the soggy tropical system farther south, he said, and pull rain over South Florida.

Forecasters expect the front to stall over the Florida Keys, meaning Miami-Dade and Monroe counties are likely to get the most rain.

While the 2014 hurricane season, which ends Nov. 30, has remained largely quiet in Florida, late-season storms can be tricky and deliver punishing winds and rain. In 2005, Hurricane Wilma sailed out of the Gulf of Mexico a week before Halloween and caused $17 billion in damage to the state. Hurricane Sandy triggered massive flooding in the Northeast in 2012 after it landed in New Jersey on Oct. 29.

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BREAKING NEWS: Energetic Jets from Young Stars Formed by Magnetic Fields

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The team of scientists from France, Canada, Italy, Germany, the United Kingdom, Russia, Japan, and the United States demonstrated that stellar jets can be confined by a large-scale magnetic field aligned with their axis.

“Not only is it consistent with current astrophysics data, the…

The team of scientists from France, Canada, Italy, Germany, the United Kingdom, Russia, Japan, and the United States demonstrated that stellar jets can be confined by a large-scale magnetic field aligned with their axis.

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“Not only is it consistent with current astrophysics data, the proposed mechanism helps explain intriguing X-ray emissions that have been observed along the jets by the Chandra space telescope,” explains INRS professor emeritus Henri Pépin, who took part in the research. “This same mechanism could be at play in other types of astrophysical jets like white dwarfs, neutron stars, and black holes.”

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As part of the project, the scientists developed a model of the interstellar magnetic field in order to study the plasma jets of emerging stars. They were able to simulate this phenomenon in the lab for the first time using an experimental platform combining high intensity lasers and intense magnetic fields. After producing plasma at small scale typical of the atmosphere of young stars, the researchers generated a magnetic field representative of the interstellar environment inside a few cubic centimeters for a few millionths of a second.

Supercomputers were then used to model emerging young stars as well as the laboratory experiment. These simulations confirm the key role of interstellar magnetic fields in creating, accelerating, and directing the jets that travel astronomical distances.

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