April 14, 2011 by staff
Yellowstone Supervolcano, Geophysicists at the University of Utah became the first large-scale photo of the electrical conductivity of the giant plume of hot rock underground and partly melted feeding the Yellowstone supervolcano. The image suggests the boom is even bigger than it looks in the pictures above facts with earthquake waves.
“It’s like comparing ultrasound and magnetic resonance imaging in the human body are different imaging technologies,” says Professor Michael Zhdanov geophysics, author of the new study and an expert in the measurement of magnetic and electric fields on the surface of the Earth for oil, gas, minerals and underground geological structures.
“It’s a totally new and different from the image and look in the Yellowstone volcanic roots,” says study co-author, Robert B. Smith, professor emeritus and research professor of geophysics and coordination of a scientist at the Yellowstone Volcano Observatory.
The new study, University of Utah has been accepted for publication in the journal Geophysical Research Letters, which plans to publish in the coming weeks.
In a December 2009 study, Smith used seismic waves from earthquakes to more detailed seismic images yet of the “hotspots” of plumbing that feeds the volcano in Yellowstone. Seismic waves move faster through cold rock and more slowly through hot rocks. Measurements of seismic wave velocities were used to make a three-dimensional image, absolutely as X-rays combine to make a medical CT scan.
The 2009 showed images of the falling column of hot, melted rock to the bottom of Yellowstone at an angle of 60 degrees and extends 150 kilometers west-northwest at a point at least 410 miles on the border of Montana, Idaho – in terms of seismic imaging could “see.”
In the new study, images of the electrical conductivity of the Yellowstone plume – generated by molten silicate rock salt mixed hot water partly molten rock – shows the leading part of the more gently dipping pen at an angle of about 40 degrees west, and extending perhaps 400 miles from east to west. Geoelectrical image can “see” only 200 kilometers deep.
Two views of the Yellowstone plume
Smith said that the geoelectric and seismic images of the Yellowstone plume, a little different because “things are slightly different images.” highlight seismic imaging materials such as molten or partially molten rock slow seismic waves, whereas the geoelectrical image is sensitive to saline fluids that conduct electricity.
“It [the pen] is very conductive compared to the rock around,” said Zhdanov. “It is near seawater conductivity.”
Pen tilt under geoelectrical image raises the possibility that the reflected seismic boom in the form of something like a tornado inclined, can be wrapped by a wider, partly covered underground molten rock and liquid, and Zhdanov Smith says.
“It’s a larger size on image geoelectrical, says Smith. “We can infer that there is more liquid,” which shows the seismic images.
Despite the differences, he says, “this body that conducts electricity is roughly the same place with a similar geometry to the Yellowstone plume seismically image.”
Zhdanov said that last year, researchers presented preliminary findings at a meeting to compare electrical and seismic in the Yellowstone area, but only at shallow depths and in a smaller area.
The study was conducted by Zhdanov, Smith, two members of the Zhdanov lab – Alexander Gribenko geophysical geophysics doctoral student and Marie Green – and the science team Martin Cuma, University of Utah Center for High Performance Computing. The funding came from the National Science Foundation (NSF) and the Consortium for Electromagnetic Modeling and Investment, who heads Zhdanov.
The Yellowstone hotspot at a glance
The new study says nothing about the possibility of another cataclysmic caldera (crater giant) eruption in Yellowstone, which has produced three disasters in the last million years.
Almost 17 million years, the plume of hot, melted rock in part known as the Yellowstone hotspot emerged for the first time around what is now the border of Oregon, Idaho and Nevada. In North America drifting slowly southwest of the hotspot, more than 140 gigantic caldera eruptions – the type of largest known eruption on Earth – along a road heading northeast now Idaho Snake River Plain.
The access point finally came to Yellowstone about 2 million years, producing three huge caldera eruptions, about 2 million, made 1.3 million and 642,000 years. Two of the eruptions covered half of North America with ash, volcanic ash occurs, 500 times and 1,000 times, respectively, than the eruption of Mount St. Helens in Washington State. Smaller eruptions occurred at Yellowstone between the big explosions and as recently as 70,000 years ago.
Seismic and ground deformation studies, which previously showed the top of the volcanic plume rise flattens like a pancake than 300 kilometers in width from 50 miles beneath Yellowstone. There, giant bubbles of hot, melted rock in hand, breaking the top of the pen and slowly, to feed the magma chamber – a spongy, the banana-shaped body of the merger and the partially molten rock located about 4 miles to 10 miles below the earth in Yellowstone.
Geoelectrical image calculation of the Yellowstone Hotspot Plume
Zhdanov and his colleagues used data collected by EarthScope, an NSF-funded effort to collect seismic data, magnetotelluric and geodetic (ground deformation) to study the structure and evolution of North America. Using data from the image of the Yellowstone plume was a challenge for both computer data was involved.
Investment is a formal mathematical method used to “extract information about geological structures deep in the earth from electric and magnetic fields recorded on the soil surface,” says Zhdanov. The investment is also used to convert measurements of seismic waves on the surface in underground images.
Magnetotelluric measurements record very low frequency electromagnetic radiation – about 0.0001 to 0.0664 Hertz – well below the frequencies of radio or television or even electrical power lines. This low frequency electromagnetic field of long wavelength penetrates a couple of hundred miles into the Earth. In comparison, radio and television waves penetrate only a fraction of an inch.
Stations in Wyoming, Montana and Idaho collected EarthScope Data – the three states straddling the Yellowstone National Park. The stations, which include electric field sensors and magnetic fields, operated by the Oregon State University Research Institutions for Seismology Company, a consortium of universities.
In a supercomputer simulation predicts an expected electrical and magnetic measurements on the surface on the basis of knowing the underground structures. This allows measurements of the actual area to be “reversed” to make an image of the underground structure.
Zhdanov said it took about 18 hours of supercomputing time to do all the calculations needed to produce the image geoelectric pen. The supercomputer was the accumulation of Ember at the University of Utah Center for High Performance Computing, said Cuma, the computer scientist.
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