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Why supervolcanoes erupt

In this device, magma samples were compressed and heated to 1,700°C and examined using X-rays

blascha faust / esrfIn this device, magma samples were compressed and heated to 1,700°C and examined using X-raysblascha faust / esrf

In a laboratory in Grenoble, France, researchers have reproduced the pressure and temperature conditions of the magma chambers of supervolcanoes and have been able to identify what triggers colossal eruptions capable of altering the climate, like Mount Pinatubo in 1991, which lowered the planet’s temperature by 0.4°C for a few months.  60,000 years ago the eruption of a supervolcano released over a thousand cubic kilometers of ash, gas and lava into the atmosphere and created a huge crater whose center is located in what is today Yellowstone Park in the United States.  The researchers placed minuscule samples of rock between two tungsten tips and submitted them to temperatures of 1,700°C and pressures of 36,000 atmospheres to simulate the magma chambers of supervolcanoes.  The measurements, made using synchrotron light, indicated that eruptions can occur spontaneously, activated only by the magma pressure, without the need for an external action or pressure (Nature Geoscience, January 2014).  The pressure resulting from the density difference between the liquid and solid magma, already crystallized in rocks, was enough to break open kilometers of crust above the magma chambers and start a violent eruption.  Team member Wim Malfait, of the Swiss Federal Institute of Technology Zurich, described the phenomenon by comparing the ascent of magma as a result of the density difference to a soccer ball filled with air under water, which is forced upward because it is surrounded by denser water.