The Power of Supervolcanoes

By Rachel Roberts

1405385_25816951According to a new study by researchers at the University of Utah, a magma reservoir under the Yellowstone supervolcano contains enough magma to fill the Grand Canyon 11 times (keep in mind the Grand Canyon is approximately 1,000 cubic miles). Supervolcanoes are volcanoes with the capacity to produce more than 240 cubic miles or rock and other debris during eruptions.

The discovered magma reservoir is estimated to be about 12 to 28 miles under the supervolcano and 4.4 times bigger than the previously known magma chamber under the volcano.

The reservoir has been the same size for quite some time, but by using seismometers to measure the noise of earthquakes to take a sonogram of the earth’s crust, researchers were able to get a more accurate picture of what is actually going on beneath the surface at Yellowstone.

1405611_42122103Contrary to popular belief, magma reservoirs are not filled with molten rock. The chamber is sponge-like and mostly solid, with pockets of molten rock inside. The study found that the upper magma reservoir of the volcano is only about 9 percent molten rock, while the lower magma reservoir is only about 2 percent.

According to researcher Hsin-Hua Huang at the University of Utah, this is the first time “we have imaged the continuous volcanic plumbing system under Yellowstone. That includes the upper crustal magma chamber we have seen previously plus a lower crustal magma reservoir that has never been imaged before and that connects the upper chamber to the Yellowstone hotspot plume below.”

ScienceMag estimates that the last time the supervolcano erupted was 640,000 years ago. It previously erupted 1.3 million and 2.1 million years ago. If the supervolcano were to erupt today, it would cover most of North America in volcanic ash. The chances of that happening, however, are 1 in 700,000 based on a report by the United States Geological Survey.

1402803_27933144Even though an explosion isn’t expected for at least a thousand years, in 2003, the ground temperatures at Yellowstone got high enough to dry out geysers and boil the sap in some of trees. Thermometers recorded temperatures of about 200 degrees Fahrenheit just below the surface. Park officials had to temporarily close down Yellowstone to keep people from burning their feet and to keep tires from melting on the roads.

So the next time you find yourself at Yellowstone National Park, take a moment to think about the natural beauty that is the supervolcano and the power it harbors just below the surface.


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