Water Fuels Explosive Volcanoes
ByNew research suggests that water plays in integral part in a volcano eruption.
Researchers at the University of Oregon tapped water in surface rocks to show how magma forms deep underground and produces explosive volcanoes in the Cascade Range.
"Water is a key player," Paul J. Wallace, a professor in the UO's Department of Geological Sciences and coauthor of a paper, said in a statement. "It's important not just for understanding how you make magma and volcanoes, but also because the big volcanoes that we have in the Cascades -- like Mount Lassen and Mount St. Helens -- tend to erupt explosively, in part because they have lots of water."
For the study, researchers examined water and other elements contained in olivine-rich basalt samples that were gathered from cinder cone volcanoes that surround Lassen Peak in Northern California, at the southern edge of the Cascade chain.
The discovery helps solve a puzzle about plate tectonics and the Earth's deep water cycle beneath the Pacific Ring of Fire, which scientists began studying in the 1960s to understand the region's propensity for big earthquakes and explosive volcanoes. The ring stretches from New Zealand, along the eastern edge of Asia, north across the Aleutian Islands of Alaska and south along the coast of North and South America. It contains more than 75 percent of the planet's volcanoes.
Next, the team fed data gained from the rocks into a complex computer model developed by co-author Ikudo Wada, then of Japan's Tohoku University. She has since joined the University of Minnesota.
The findings are detailed in the May issue of Nature Geoscience.