A research team from the University of Utah reported Thursday in the journal Science that they have found a missing link in Yellowstone National Park’ underground volcanic structure – a huge reservoir of magma.
The reservoir mainly contains solid hot rock, but some of the rock formations are melted. The newly-found reservoir is nearly 5 times larger than the magma chamber located above it. Scientists claim that the magma in the reservoir could fill the entire Grand Canyon.
Additionally, the reservoir sits on a large mantle plume that carries hot magma from the Earth’s hot core to surface layers . Yellowstone’s volcanic system remained nearly unchanged for 17 million years with slight deviations caused by shifts in the North American tectonic plate. This plate usually moves about an inch every year southwestwards.
As a result, Oregon, Nevada and Idaho have a complex system of empty calderas that marked the tectonic plate’s movements. Similar tectonic activity was detected in the Hawaiian Islands, when the Pacific plate crossed over a volcanic hot spot causing a series of volcanoes to resume activity.
But Yellowstone hosts one of the largest volcanoes in the world. Scientists claim that a Yellowstone eruption would be nearly 1,000 times more violent than Mount St. Helens eruption in 1980. The ripple effects would be felt at a global scale, so scientists seek to monitor the giant sleeping volcano as closely as they can.
Utah researchers explained that Yellowstone’s updated volcanic system looked like a giant conduit or a pipe that starts down at 1,000 kilometers. Yet, the complete image of the system does not alter the current risk assessment of the volcano. Instead it helps researchers gain a complete view on its mechanics.
“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,”
acknowledged Jamie Farrell, a co-author of the paper and researcher at the University of Utah.
Mr. Farrel also admitted that no scientist was able to witness a really large volcanic eruption. Instead, researchers usually scale small-scale eruptions on Yellowstone’s size and try to figure out what causes them.
Currently, scientists believe that the next calderic eruption could occur northeast of the current giant crater, or caldera. They estimate that the magma reservoir located beneath the magma chamber could be filled with enough magma to create a new caldera to the northeast through a series of explosions.
Yellowstone witnessed a calderic eruption about 640,000 years ago. The resulting giant crater was about 25-by-37 mile-wide. In the meantime the caldera was masked by lava flows and the Yellowstone Lake which partially filled the area. The only sign that Yellowstone sits on an old caldera is the lack of any mountain at the core of the park because mountains were virtually pulverized during the last eruption.
During their study, scientists used seismic data to map Yellowstone’s volcanic system. Yellowstone is very active and has hundreds of small quakes every year. But the speed of the quakes can vary greatly due to the materials they have cross to reach surface. For instance, in hot rock layers, seismic waves move slower, while in cold rock layers they usually speed up.
By analyzing data provided from several sensors, the Utah team was able to obtain an accurate map of the cold and hot rock layers beneath Yellowstone.
Image Source: Volcanic News Eruptions (blog)