Tag Archives: yellowstone volcano

Yellowstone Geyser

New Yellowstone study suggests volcanic activity is more frequent than previously thought

The Yellowstone super volcano, which basically outlines the whole Yellowstone National Park, is part of one of the most active volcanic regions in the world. A recent research conducted by a joint team of international scientists from Washington State University and the Scottish Universities Environmental Research Centre is set to cast doubts on the frequency of eruptions and, most importantly, super eruptions from the Yellowstone area, which the team found to be more frequent than previously thought.

Yellowstone GeyserYellowstone’s many attractions include geysers, such as Old Faithful, and hot springs, which have been formed, it is believed,  a result of the giant pool of magma that Yellowstone sits on. Beyond its serene and truly beautiful status today, Yellowstone is one of the most dangerous patches on Earth. Its largest eruption took place some 2.1 million years ago, and in the subsequent spew of lava and ash over half of the United States was covered in a dark shroud blocking sun light, and reaching areas of as far away as Texas, Louisiana and southern California, according to the U.S. Geological Survey.

This two-million-year-old lava deposit has three layers.

“That got us thinking whether these things were representing different magma batches [from a single eruption] or different events,” said study leader Ben Ellis, a volcanologist and postdoctoral researcher at Washington State University.

The team lead by Ellis analyzed rock samples from all three layers using the latest isotope dating techniques, involving the potassium 40 and argon 40 isotopes. Like a geological clock, the technique helps dating samples and have a precision of 0.2 percent. Darren Mark, study co-author at the Scottish research center, recently helped fine tune the technique to improve it by 1.2 percent. Apparently, the uppermost layer of lava was deposited some time later than the other two, hinting that a second eruption took place.

The team of researchers claim that the super eruption, which formed  massive volcanic depressions known as “calderas“, most famous of which being Huckleberry Ridge, actually took place in two different eruptions at least 6,000 years apart. The first eruption generated 2,200 cubic kilometers of volcanic material, while the second, smaller eruption generated 290 cubic kilometers. As a measure of comparison, the infamous Mount St. Helens volcanic eruption from 1980 produced about 1 cubic km of volcanic material.

These latest findings, which were reported in a recent paper published in the journal Quaternary Geochronology, suggest that the Yellowstone super eruption are less powerful, and more frequent at the same time than previously thought. Also, the study suggest that the volcanic formation known as the Island Park Caldera is more active than previously thought and could help geologists to more accurately predict its next seismic event. The caldera is actually comprised of two smaller calderas and stretches 58 miles from Wyoming to Idaho. The last known Yellowstone eruption to cause a lava flow was about 70,000 years ago, smaller steam-only eruptions have caused seismic events like the one at Yellowstone Lake almost 14,000 years ago that created a 5 km crater.

source: national geographic 

Geophysics shows plume of Yellowstone volcano is much larger than previously believed

Yellowstone is without a doubt one of the most fascinating places on the face of the planet. But it doesn’t only attract families or people who want to relax, but it attracts scientists as well, and among them, geologists and geophysicists hold a top spot. University of Utah researchers made the first large-scale picture of the electrical conductivity of the enormous underground plume of hot and partially molten rock that feeds the Yellowstone volcano. The image suggests that it is much bigger than previously thought before, when it was also investigated with geophysical methods, but in the form of seismic waves.

“It’s like comparing ultrasound and MRI in the human body; they are different imaging technologies,” says geophysics Professor Michael Zhdanov, principal author of the new study and an expert on measuring electric and magnetic fields, with the purpose of investigating underground objectives.

In a previous 2009 study, researchers (Smith) used seismic waves from earthquakes to make an accurate image of the plume that feeds the volcano. In addition to other factors, seismic waves travel faster in cold rocks and slower in hotter rocks, so seismic velocity information can be used to make a pretty accurate 3D picture, much like X-rays are combined to make a medical CT scan.

But in this type of cases, electric measurements can be much more direct and offer much more answers, but they measure slightly different things. Seismic analysis shows which rocks are hotter and slow down waves, while electric measurements show the conductivity of the rocks, and is especially sensible to briny fluids that conduct electricity.

“It [the plume] is very conductive compared with the rock around it,” Zhdanov says. “It’s close to seawater in conductivity.”

The new study doesn’t say anything about the chances of a catastrophic eruption at Yellowstone, but it does seem to suggest than when it is going to come, it will be bigger than previously expected.

Yellowstone Volcano Inflating With Molten Rock At Record Rate

yellowstone


Yellowstone is being visited by over 2 million tourists every year and it spans an area of 3,472 square miles (8,987 km²) which makes it North America’s largest volcanic field. The main interest was around the Old Faithful Geyser and the Yellowstone Lake which is the largest high-altitude lake in North America and is centered over the Yellowstone Caldera.But now everybody is following the “supervolcano” which rose at a record rate since mid-2004, likely because a Los Angeles-sized, pancake-shaped blob of molten rock was injected 6 miles beneath the slumbering giant, University of Utah scientists report in the journal Science. It is produced by a “hotspot” — a gigantic plume of hot and molten rock — that begins at least 400 miles beneath Earth’s surface and rises to 30 miles underground, where it widens to about 300 miles across. The magma chamber gets supplies from there; scientists think that the magma chamber begins about 5 miles beneath Yellowstone and extends down to a depth of at least 10 miles.

But they say that we should not worry. “There is no evidence of an imminent volcanic eruption or hydrothermal explosion. That’s the bottom line,” says seismologist Robert B. Smith, lead author of the study and professor of geophysics at the University of Utah. “A lot of calderas [giant volcanic craters] worldwide go up and down over decades without erupting.”. But there is no evidence that an imminent volcanic eruption is not going to take place. Chang, the study’s first author, says: “To say if there will be a magma [molten rock] eruption or hydrothermal [hot water] eruption, we need more independent data.”.

What they know is that from mid-2004 through 2006, the Yellowstone caldera floor rose as fast as 2.8 inches (7 centimeters) per year — and by a total of 7 inches (18 centimeters) during the 30-month period. The uplift has not stopped but it is a bit slower; when rising molten rock reaches the top of the magma chamber, it starts to crystallize and solidify, releasing hot water and gases, pressuring the magma chamber. The most recent giant eruption created the 40-mile-by-25-mile oval-shaped Yellowstone caldera.