Mega volcanoes could have detectable precursors

BBC : Earth’s largest volcanoes may signal impending eruptions earlier than previously thought, according to a new study in Nature. Tim Druitt of Blaise Pascal University in France and colleagues analyzed crystals in pumice rock from the Greek island of Santorini, site of the Minoan eruption in the late 1600s BC, and found that magma built up under the surface over a period of a few decades before the event. Given the 18 000year period between the caldera’s Bronze Age eruption and the previous one, that’s a surprisingly short amount of time for the magma reservoir to recharge. Long-term monitoring of dormant but potentially active caldera systems could pick up on seismic indications of magma buildup, which could make the difference for any preparation efforts needed to stem loss of life.