Yellowstone Supervolcano's Size Exceeds Expectations

Beneath Yellowstone National Park lurks a partially molten plume rising from the Earth's mantle, fueling the park's famous geysers and hot springs, and causing the crust above to bulge and recede in response to its forces.
Now researchers report that the source beneath the surface may be even more massive than previously thought. Using a new technique, they have created an image of the plume beneath Yellowstone showing the cyclone shape stretching at a 40-degree angle to the west at a depth of 200 miles for 400 miles east to west, as far as the new technique can reach.
This study does not make any predictions about future eruptions, which the USGS Yellowstone Volcano Observatory notes are of very low probability in any given millennium, since they have been separated in the past by 800,000 and 660,000 years.
When the Yellowstone supervolcano last erupted cataclysmically 640,000 years ago, it formed the Yellowstone Caldera, a 30 by 50 mile crater. Smaller, non-explosive eruptions have happened since, the most recent about 70,000 years ago.
Previous estimates of the plume have used seismic images, which measure the reflection of seismic waves from earthquakes off of different types of materials below the surface. They reached even deeper than the new images -- to more than 400 miles down.
The new method detects differences in electrical conductivity generated by the different types of rocks and minerals below Yellowstone National Park, which provides clues to what they are made of.
Using supercomputers, the research team, led by Michael Zhdanov of the University of Utah in Salt Lake City, created images of the plume based on the electromagnetic measurements from 115 stations in Idaho, Montana and Wyoming.
"We see that there is a partially melted, conductive plume at great depths starting in the mantle, and going up," Zhdanov said.
"It's a completely different technique, completely different data," he added. "It confirms that the plume is there, but it provides another view of the plume."
The plume's high conductivity suggests it contains high levels of silicate rocks and perhaps briny water, he said. The observation that the high conductivity plume is larger and angled differently than the one found with seismic imaging suggests that the plume of molten and partially molten rock may be surrounded by additional liquid including briny water, Zhdanov said.
"I think it's an important finding to have a new technique to corroborate the way that this hotspot is rising through the mantle," said Jake Lowenstern, USGS scientist in charge of the Yellowstone Volcano Observatory.
He noted that the finding does not indicate that the plume of molten material is necessarily bigger than earlier seismic images indicated, but that the plume's sphere of influence extends further than could be seen by the other technique. "You're looking at the effects of that plume but not necessarily the plume itself," he said.
"It doesn't have great effect on the actual risk from the much more shallow volcanic system," he added. While this plume provides the heat that ultimately reaches the surface, he said, with these new images, "you're looking at something that's way below the actual magma chamber that's responsible for the eruptions."

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8.6 Magnitude Earthquake Strikes North Sumatra

UPDATE (7:33 a.m. ET): An aftershock of magnitude 8.2 has struck at 16.4 km (10 miles) deep - at 617 km (383 miles) south southwest of the coast of Banda Aceh. We are continuing to monitor the situation. Follow sea level changes here.
A magnitude 8.6 earthquake struck North Sumatra, Indonesia, at 2:38 p.m. local time today. First estimated as a magnitude 8.7 by the U.S. Geological Survey, the earthquake originated 22.9 km (14.2 miles) below the Earth's crust and struck 434 kilometers (270 miles) southwest of the coast of Banda Aceh, the capital of Indonesia's Aceh province.

A tsunami watch and warning was put into effect for the Indian Ocean, immediately after the event. The power is out in Banda Aceh, where residents have moved to high ground, reported Sutopo Purwo Nugroho, a spokesman for the Indonesian National Disaster Management Agency.
The island of Simeulue, Prih Harjadi, and other coastal areas of Aceh are also on alert.
India has taken caution on Andaman and Nicobar Islands, where authorities have ordered people to move out of low-lying areas, CNN reported.
However the geophysics of today's quake do not indicate a repeat of Indonesia's 2004 earthquake is in progress. The magnitude 9.1 earthquake that struck in 2004 and triggered a tsunami that killed more than 200,000 people in 14 countries was a subduction megathrust earthquake closer to shore (250 kilometers south-southeast of Banda Aceh).
Today's temblor appears to have ripped along a transform fault, tearing the seafloor as opposed to popping it apart. Though local tsunami waves are a considerable risk, with calculations showing Simeulue could receive waves as high as 6 meters (20 feet) the widespread tsunami damage seen in 2004 is not anticipated.

IMAGES: Earthquake location map (USGS) Indian Ocean warning in effect (PTWC)

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Monster Solar Tornadoes Discovered

For the first time, huge solar tornadoes have been filmed swirling deep inside the solar corona -- the sun's superheated atmosphere. But if you're imagining the pedestrian tornadoes that we experience on Earth, think again.
These solar monsters, measuring the width of several Earths and swirling at speeds of up to 300,000 kilometers (190,000 miles) per hour, aren't only fascinating structures; they may also trigger violent magnetic eruptions that can have drastic effects on our planet.

In one example observed on Sept. 25, 2011, solar researchers from the UK used the high-definition cameras onboard NASA's Solar Dynamics Observatory (SDO) to track solar gases as hot as 2 million Kelvin (3.6 million degrees Fahrenheit) getting sucked from the bottom of a solar prominence and spiral high into the corona. The solar tornado then developed for three hours, gases traveling in spiral paths for around 200,000 kilometers (120,000 miles).
"Prominences are tangled magnetic fields trapping cold and dense plasma in the solar corona," Xing Li, solar physicist at Aberystwyth University, told Discovery News. "These often erupt spectacularly and fly out into space as coronal mass ejections (CMEs), and large CMEs will impact our space weather and space technology in a significant way when they are heading toward the Earth.
"What drives these eruptions is still not clear and is very important to gain an understanding of CME initiation (so that we can possibly predict such events)."

As mankind becomes more dependent on sensitive technology, it is critical that we develop new and more sophisticated ways to predict the sun's next "temper tantrum." As it turns out, these twisted tornadoes may hold the key to predicting when the next CME will be launched.
"This unique and spectacular tornado must play a role in triggering global solar storms," said co-discoverer Huw Morgan, also at Aberystwyth University.

"These tornadoes may help to produce favorable conditions for CMEs to occur," Li added, pointing out that the tornadoes his team studied coincided with CME eruptions as observed by other instruments monitoring the wider corona.
Also, the tornadoes observed so far by Li and Morgan often occur at the root of where CMEs are initiated. As the dynamic structures wind-up magnetic fields and drag powerful electric currents high into the corona, these tornadoes could generate the conditions ripe for CME eruptions, they theorize.

But to observe the tornadoes in the first place requires a bit of luck.
Firstly, as they are magnetic structures, if the tornado is empty of radiating plasma, they will remain invisible. Only when hot plasma is being dragged high into the corona can they be seen. Conversely, should the tornado be completely flooded with plasma, you wouldn't see the motion of the material as the radiating plasma would be completely washed out.

Li highlights the need for discrete objects inside the swirling mass so they can be tracked as they move around the tornado. He likens this to the dust and bits of debris that a terrestrial tornado would pick up. Without these objects, we couldn't "see" the spinning wind currents. The same goes for solar tornadoes; discrete "blobs" of plasma can be tracked as they are accelerated and carried high into the corona by the tornado's magnetic field.
"Also, we believe that the angle you view the tornado from is important," Li added. "For example, if you imagine the slinky structure mentioned above, if you view it from the side it may not appear so clearly as a tornado."
In the past, observers have spotted prominences that they described as "tornadoes," but in the days before the SDO was launched, the necessary definition and rapid image capturing techniques simply weren't available.

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