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Can the ash
From an erupting
Volcano
Be scoured
From the
The earth and sky?
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Can the ash
From grieving hearts
Be swept back
Into the caldera,
To be as
It was before?
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Bear … 03.12.2015
ⓒBearspawprint2015
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Olympus Mons (pictured) is regarded as the largest volcano in the Solar System, but there is a new kid on the block. NASA
A megavolcano found at the bottom of the Pacific Ocean is being reported as the largest single volcano on Earth. Tamu Massif, as the megavolcano is called, may be as voluminous as Olympus Mons on Mars, which is regarded as the Solar System’s largest known volcano.
Tamu Massif, the inactive volcano, was previously thought to be a string of volcanoes rather than one enormous feature. It is part of an underwater mountain range called the Shatsky Rise, which covers an area as large as California state in the US. Found close to the east of the coast of Japan, Shatksy Rise formed some 145 million years ago as huge amounts of magma flowed onto the ocean floor at a point where three microplates of Earth’s crust meet.
While Olympus Mons is much taller (>25km) than Tamu Massif (about 4km), its base is smaller. Massive lava flows would have rapidly flowed along shallow slopes to create Tamu Massif, which has a 650km-wide base, nearly as big as New Mexico in the US. Volcanoes created entirely due to such lava flow are called shield volcanoes because they resemble a warrior’s shield.
The volcano’s structure is described in the journal Nature Geoscience by scientists from the US, the UK and Japan. Tamu Massif is named after Texas A&M University, where the lead researcher William Sager is based.
Although rocks from Tamu Massif had previously been identified as volcanic crystallised lava, its size made geologists believe it was the result of many volcanic eruptions that may have occurred over a period of many millions of years. Now it seems that this may have been closer to a distinct but enormous flood of lava.
To verify that hypothesis Sager’s team collected new samples and data aboard an ocean-going science research vessel called Marcus G. Langseth. They drilled samples from the ocean floor, and poked Tamu Massif with seismic waves, measuring the response using seismometers. They were able determine whether the rocks may have come from different eruptions. From all the new data they acquired it seems that lava flow emerged from a single central magma vent.
Time on such research vessels is expensive and this report is first of its kind looking at large underwater volcanoes. Much of Earth’s ocean floor remains to be thoroughly explored. This makes Sager believe that there may be even bigger volcanoes out there.
A megavolcano found at the bottom of the Pacific Ocean is being reported as the largest single volcano on Earth. Tamu Massif, as the megavolcano is called, may be as voluminous as Olympus Mons on Mars, which is regarded as the Solar System’s largest known volcano. Tamu Massif, the inactive volcano…
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| Yellowstone is an active volcano. Surface features such as geysers and hot springs are direct results of the region’s underlying volcanism. CREDIT: National Park Service |
SALT LAKE CITY — Yellowstone’s underground volcanic plumbing is bigger and better connected than scientists thought, researchers reported here today (April 17) at the Seismological Society of America’s annual meeting.
“We are getting a much better understanding of the volcanic system of Yellowstone,” said Jamie Farrell, a seismology graduate student at the University of Utah. “The magma reservoir is at least 50 percent larger than previously imaged.”
Knowing the volume of molten magma beneath Yellowstone is important for estimating the size of future eruptions, Farrell told OurAmazingPlanet.
Supervolcano trail
Geologists believe Yellowstone sits over a hotspot, a plume of superheated rock rising from Earth’s mantle. As North America slowly drifted over the hotspot, the Yellowstone plume punched through the continent’s crust, leaving a bread-crumb-like trail of calderas created by massive volcanic eruptions along Idaho’s Snake River Plain, leading straight to Yellowstone. The last caldera eruption was 640,000 years ago. Smaller eruptions occurred in between and after the big blasts, most recently about 70,000 years ago. [Infographic: Geology of Yellowstone]
The magma chamber seen in the new study fed these smaller eruptions and is the source of the park’s amazing hydrothermal springs and geysers. It also creates the surface uplift seen in the park, said Bob Smith, a seismologist at the University of Utah and author of a related study presented at the meeting.
The volcanic plume of partly molten rock that feeds the Yellowstone supervolcano. Yellow and red indicate higher conductivity, green
and blue indicate lower conductivity. Made by University of Utah geophysicists and computer scientists, this is the first large-scale ‘geoelectric’ image of the Yellowstone hotspot.
Scientists have updated this image of Yellowstone volcano’s underground magma chamber. Instead of two big yellow blobs, they have a clearer picture that looks like a knobby banana. CREDIT: Jamie Farrell, University of Utah
“This crustal magma body is a little dimple that creates the uplift,” Smith said. “It’s like putting your finger under a rubber membrane and pushing it up and the sides expand.”
Clearer picture
A clearer picture of Yellowstone’s shallow magma chamber emerged from earthquakes, whose waves change speed when they travel through molten or solid rock. Farrell analyzed nearby earthquakes to build a picture of the magma chamber.
The underground magma resembles a mutant banana, with a knobby, bulbous end poking up toward the northeast corner of Yellowstone National Park, and the rest of the tubular fruit angling shallowly southwest. It’s a single connected chamber, about 37 miles (60 kilometers) long, 18 miles (30 km) wide, and 3 to 7 miles (5 to 12 km) deep.
Previously, researchers had thought the magma beneath Yellowstone was in separate blobs, not a continuous pocket.
The shallowest magma, in the northeast, also matches up with the park’s most intense hydrothermal activity, Farrell said. The new study is the best view yet of this zone, which lies outside the youngest caldera rim.
Additional molten rock, not imaged in this study, also exists deeper beneath Yellowstone, scientists think.
Original article on LiveScience’s OurAmazingPlanet.
Yellowstone and Yosemite: Two of the World’s Oldest National Parks
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A restive “super volcano” west of Naples is raising nervousness in the local Italian population. The ground of the Campi Flegrei (“burning fields”), also known as the Phlegraean Fields, has risen more in recent weeks than it has in a long time. Location of Campi Flagrei is close to African-Eurasian plate boundaries.
Italy’s Deparment of Civil Protection recently raised the alert level for the Phlegraean Fields, where Wiersberg said the ground was rising by about three centimetres a month. There are concerns that a magma chamber under the fields – presumably connected to the one under Mount Vesuvius, east of Naples – is filling up, the rising pressure possibly heightening the danger of an eruption.
Wiersberg is part of an international research team that began drilling into the ground not far from the caldera last summer to monitor possible early warning signs of an eruption.
“Many houses cracked,” after which the ground deformation sharply subsided, Wiersberg said. “But it’s true that the uplift has increased again during the past two or three months.” An eruption could have serious consequences for the heavily populated region with knock-on effects for the whole of Europe. There could also be worldwide impact, for example in the form of climatic changes. No forecasts have been made thus far. Since super volcanoes seldom undergo massive eruptions, empirical data is lacking. “It’s easy to assert there’ll be an eruption sometime. That doesn’t help us, though. We need more specific information,” Wiersberg said. He said the drilling project aimed in part to monitor the Phlegraean Fields over the long term and gain more knowledge of what had occurred earlier in the super volcano. “First we’ve got to understand what’s happening under the surface,” Wiersberg said. Then it may be possible to say more about the likelihood of an eruption.
Image by: Donarreiskoffer/ Wikimedia Commons
“” underwater volcanic eruptions and magma flows on the sea floor have been seen for the first time ever thanks to video captured by NOAA. James Williams talks to the lead scientist on the project to learn the story behind the explosive images.””
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