Magma stored under volcanoes is mostly solid
Analysis of crystals found in lava suggests shift to molten goo occurs close to eruption
UP AND OUT Seven hundred years ago, a New Zealand volcano (a 19th century eruption is illustrated here) spewed out seven zircon crystals that are providing a peek at the state of magma in underground chambers.
Charles Blomfield
Most of a volcano’s magma probably isn’t the oozing, red-hot molten goo often imagined.
Analyses of zircon crystals, spewed from a volcanic eruption in New Zealand, show that the crystals spent the vast majority of their time underground in solid, not liquid, magma, researchers report in the June 16 Science. The results suggest the magma melted shortly before the volcano erupted.
This finding helps confirm geologists’ emerging picture of magma reservoirs as mostly solid masses, says geologist John Pallister of the U.S. Geological Survey in Vancouver, Wash., who was not involved in the study. And it could help scientists more accurately forecast when volcanoes are poised to erupt.
Studying magma reservoirs directly is difficult because they’re buried kilometers underground. Heat and pressure would destroy any instruments sent down there. So Kari Cooper, a
