Yellowstone National Park is sitting on a magma field that, if erupted, would be 1,000 times bigger than Mount St. Helens. For those who are trying to fathom this, the magma in the two huge reservoirs underneath the park could cover approximately 4,063 soccer fields or fill over 11 Grand Canyons. In a comforting statement, seismological experts say the discovery of these gigantic magma pools does not actually increase the potential for what would be a catastrophic eruption. However, it does have them paying closer attention.
Experts were already aware of the main Yellowstone magma pool that powers the volcanic phenomena in the park and also caused the historic eruptions 640,000, 1.2 million and two million years ago. Recent exploration provided the discovery of the second magma chamber that is located anywhere from 12 to 28 miles under the park. This pool is 4.5 times bigger than the previously-known magma pool.
Magma is defined as the hot material beneath the earth’s crust that is in various stages of fluidity. The familiar surface-eruptive materials, lava and igneous rocks, are formed from magma. This discovery is extremely important because it will allow scientists to study how magma travels from the earth’s mantle to the surface. With a volume of 11,500 cubic miles, this reservoir of magma could generate an enormous amount of lava, making Mount St. Helens look like a small geyser eruption that Yellowstone is so well know for. Although it is considered officially inactive, these magma pools make Yellowstone the world’s largest volcano.
This report was prepared using technology that is most similar to the medical version of an MRI. This region of the United States that stretches from Oregon and Idaho all the way to southern Nevada is home to much seismic activity. The key manifestations of this activity are earthquakes that follow the route of the North American tectonic plate as it creeps southward at about one inch per year. One can trace the progress of this movement from remnant calderas – craters from the collapsed terrain that is left after volcanic eruptions.
No one in history has witnessed an eruption of the potential magnitude of a Yellowstone eruption. To date, the deadliest and largest scale eruption in the United States is the 1980 eruption of Mount St. Helens. This catastrophic event, occurring after an earthquake of 5.1 on the Richter scale, killed 57 people and destroyed hundreds of homes, railways and roadways. Almost 4 million cubic yards of lava material flowed almost 17 miles south to the Columbia River. Ash from the eruption went as far as 16 miles into the sky and was carried as far north as Edmonton in Alberta, Canada. The May 18, 1980 eruption released 24 megatons of thermal energy; 1,600 times the energy yield released from the bomb dropped on Hiroshima.
In that the mantle beneath Yellowstone is fairly stable, the risk of the magnitude of seismic activity required to unleash this catastrophic eruption is small. Less than two percent of the magma is molten in the reservoir closest to the surface. However, with the potential eruptive power of 1,000 Mount St. Helens, scientists are paying closer attention to Yellowstone National Park and its magma reservoirs.
By Chris Marion
Picture by Frank Kovelchek – Creativecommons Flickr License