This week, a survey will begin to map the underground hydrothermal features of Yellowstone National Park for the first time. 
 
 The U.S. Geological Survey (USGS), in collaboration with the Aarhus University in Denmark and the University of Wyoming, will use a helicopter carrying electromagnetic technology that resembles a giant hula hoop to record tiny voltage signals. 
 
 The data will be able to tell the scientists if they are flying over solid earth, “rotten” sulfuric rock, or water. Carol Finn, one of the scientists on the surveying team, said she has been looking forward to this for ten years. 
 
 “This is really kind of a last frontier if you will, in Yellowstone, of being able to look at a large part that’s underground that people that people have not looked at,” said Finn. “This survey can visualize the geology and the water down to about 500 meters, so 1500 feet.” 
 
 The goal of the project is to fill in the gaps of knowledge about what causes geysers like Old Faithful and hydrothermal explosions by locating where all that heated water flows underground. 
 
 “There’s just a lot we don’t know and this survey is really exciting because it’s going to be the first view of a large portion of the groundwater system, of the water underground that feeds all of these thermal features,” said Finn. 
 
 The survey will also provide information that could help the park in the future by locating unstable ground. The researchers will fly the helicopter along the Mammoth-Norris corridor and take at least four weeks to complete. ||||| BILLINGS, Mont. (AP) — Scientists from the U.S. and Denmark are seeking to map out the plumbing system hidden inside the earth's crust that's responsible for the famous Old Faithful geyser and other hydrothermal features at Yellowstone National Park. 
 
 Throughout November the research team will conduct flights over the park using a giant, hoop-shaped electromagnetic system suspended from a helicopter. The device acts like an X-ray to determine where and how hot water flows beneath the surface. 
 
 The team also hopes to gain insights into the infrequent but sometimes massive hydrothermal explosions that occur in the park, said lead scientist Carol Finn with the U.S. Geological Survey. 
 
 One such explosion, or possibly multiple explosions, that occurred roughly 13,800 years ago left a crater that measures 1-1/2 miles (2.6 km) across beneath at the bottom of Yellowstone Lake. It's believed to be the largest such crater in the world. 
 
 Similar to the regular eruptions of Old Faithful, hydrothermal explosions occur when huge pockets of boiling water beneath the ground experience a sudden drop in pressure, causing the water to convert to steam and explode violently to the surface. 
 
 Similar work elsewhere in the U.S. has helped reveal hazards from volcanoes. 
 
 "Nobody knows anything about the flow paths" for the hot water that erupts from Yellowstone's geysers, Finn said. "Does it travel down and back up? Does it travel laterally?" 
 
 The electromagnetic system was developed in Denmark to map out groundwater supplies in Denmark. It's able to discern between water and rocks to a depth of about 1,500 feet beneath the surface. 
 
 In Yellowstone, a better understanding of the hydrothermal plumbing could help administrators plot out future development so tourists can enjoy the park's features without damaging them or being put into harm's way. 
 
 The study is a collaboration between the U.S.G.S., Yellowstone National Park, the University of Wyoming and Denmark's Aarhus University. ||||| The gorgeous colors of Yellowstone’s Grand Prismatic hot spring are among the national park’s myriad hydrothermal features created by the Yellowstone supervolcano. A new University of Utah study reports discovery of a huge magma reservoir beneath Yellowstone’s previously known magma chamber. (“Windows into the Earth,” Robert B. Smith and Lee J. Siegel) 
 
 Yellowstone National Park is the home of one of the world's largest volcanoes, one that is quiescent for the moment but is capable of erupting with catastrophic violence at a scale never before witnessed by human beings. In a big eruption, Yellowstone would eject 1,000 times as much material as the 1980 Mount St. Helens eruption. This would be a disaster felt on a global scale, which is why scientists are looking at this thing closely. 
 
 On Thursday, a team from the University of Utah published a study, in the journal Science that for the first time offers a complete diagram of the plumbing of the Yellowstone volcanic system. 
 
 The new report fills in a missing link of the system. It describes a large reservoir of hot rock, mostly solid but with some melted rock in the mix, that lies beneath a shallow, already-documented magma chamber. The newly discovered reservoir is 4.5 times larger than the chamber above it. There's enough magma there to fill the Grand Canyon. The reservoir is on top of a long plume of magma that emerges from deep within the Earth's mantle. 
 
 [Geysers erupt because they’re all bendy inside] 
 
 This system has been in place for roughly 17 million years, with the main change being the movement of the North American tectonic plate, creeping at the rate of roughly an inch a year toward the southwest. A trail of remnant calderas can be detected across Idaho, Oregon and Nevada, looking like a string of beads, marking the migration of the tectonic plate. A similar phenomenon is seen in the Hawaiian islands as the Pacific plate moves over a hot spot, stringing out volcanoes, old to new, dormant to active. 
 
 University of Utah seismologists funded by the National Science Foundation found a pool of magma beneath Yellowstone's supervolcano that they say is big enough to fill the Grand Canyon more than 11 times. (National Science Foundation/University of Utah) 
 
 “This is like a giant conduit. It starts down at 1,000 kilometers. It's a pipe that starts down in the Earth," said Robert Smith, emeritus professor of geophysics at the University of Utah and a co-author of the new paper. The lead author is his colleague Hsin-Hua Huang. 
 
 This new picture doesn't change, fundamentally, the risk assessment of Yellowstone, but it will help scientists understand the mechanics of the volcano. 
 
 “Really getting an idea of how it works and understanding how these large caldera-forming eruptions may occur, and how they might happen, would be a good thing to understand," said paper co-author Jamie Farrell, another geophysicist at the university. "No one's ever witnessed one of these really large volcanic eruptions. We kind of scale smaller eruptions up to this size and say, 'This is probably how it happens,' but we really don’t know that for sure.” 
 
 [What Yellowstone’s Thermal Springs looked like before humans contaminated them] 
 
 The next major, calderic eruption could be within the boundaries of the park, northeast of the old caldera. 
 
 “If you have this crustal magma system that is beneath the pre-Cambrian rocks, eventually if you get enough fluid in that system, enough magma, you can create another caldera, another set of giant explosions," Smith said. "There’s no reason to think it couldn’t continue that same process and repeat that process to the northeast.” 
 
 The report is based on the equivalent of an MRI of the crust beneath Yellowstone. Nature itself supplies the key diagnostic tool: Earthquakes. The Yellowstone region is seismically active, and in any given year there can be hundreds of small earthquakes. These tremors send seismic waves racing through the planet's crust. Seismographs stationed around Yellowstone and across the United States record the arrival of these waves and carefully measure how long it took for them to reach the instruments. The speed of the waves carries information: When the seismic waves hit hot rock, they go slower; when they pass through cold rock, they're faster. By combining the data from many sensors, scientists can get a picture of the hot and cold rock beneath Yellowstone. This is known as "seismic tomography." 
 
 This is a volcano that can erupt either in a big way or a truly colossal and catastrophic way. The big eruptions can send lava flowing over a big portion of the park; the really huge ones can form a giant crater, or caldera. The last time Yellowstone had a calderic eruption was 640,000 years ago, and the misshapen hole it created was about 25 miles by 37 miles across. This caldera has since been filled in by lava flows and natural erosion, and Yellowstone Lake covers a portion of the area. The main visual evidence of the old caldera is the striking absence of mountains at the heart of the park: They were literally blown away in the last eruption. 
 
 Risk assessment is tricky for low-probability, high-consequence events like volcanic eruptions. The big Yellowstone eruptions occur on time scales of many hundreds of thousands of years. Smith said the repeat time for a caldera explosion at Yellowstone is roughly 700,000 years. But the smaller eruptions, with lava flowing over the surface, are more frequent. There have been at least 50 such smaller eruptions since the caldera exploded 640,000 years ago. The most recent was about 70,000 years ago. 
 
 Geological processes don't follow clocks. These are chaotic systems, with strain building unpredictably as distant faults break and the geological stresses shift here and there. 
 
 Bottom line: Yellowstone is unpredictable. There's no sign at all that this old volcano is going to erupt anytime soon, either in a big way or a huge, show-stopper way. But neither is there any evidence that it's running out of steam. 
 
 
 
 A new study provides the first complete view of the plumbing system that supplies hot and partly molten rock from the Yellowstone hotspot to the Yellowstone supervolcano. The study revealed a gigantic magma reservoir beneath the previously known magma chamber. This cross-section illustration cutting southwest-northeast under Yellowstone depicts the view revealed by seismic imaging. Seismologists estimate the annual chance of a Yellowstone supervolcano eruption is 1 in 700,000. (Hsin-Hua Huang/University of Utah) 
 
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– The mysteries of Old Faithful may soon be solved, thanks, in part, to something that looks like a giant hula hoop. American and Danish scientists have this week begun an aerial survey of Yellowstone that actually looks well into the earth, "visualizing" the geology and water as much as 1,500 feet below the surface, says Carol Finn. She's waited a decade to explore what she calls "a last frontier ... in Yellowstone," and the intention is to better map the flow of water that's feeding Old Faithful and rare but sometimes violent hydrothermal explosions. Over a four-week period, a helicopter will fly above, armed with electromagnetic technology that looks like a giant hula hoop. The AP explains it in layman's terms: "The device acts like an X-ray to determine where and how hot water flows beneath the surface." Scientists will use the data to determine whether solid earth, "rotten" sulfuric rock, or water lurks below, which could assist in identifying unstable areas, per Wyoming Public Media. But a press release frames the main quest like so: We know that the water that explodes from Yellowstone's geysers "originates as old precipitation, snow and rain that percolates down into the crust, is heated, and ultimately returns to the surface." We know that it can take as long as thousands of years for that process to run its course. What scientists are hoping to determine are the routes these waters take. "Does it travel down and back up? Does it travel laterally?" asks Finn. Right now, "nobody knows." (Archaeologists made a surprise find underneath a Mayan temple.)