How fast-rising magma contributed to deadly volcano
Magma from the deadly eruption of Irazú in Costa Rica decades ago, recently helped researchers better understand quickly erupting volcanos. Now scientists hope to learn more by investigating other volcanic sites.
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Does this mean that monitoring volcanoes for earthquakes more than 10 miles deep could provide early warning of impending eruptions? Not for every volcano, the researchers said. [Countdown: History's Most Destructive Volcanoes]Skip to next paragraph
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Potential for eruption forecasting
Irazú volcano is an arc volcano, rising above a subduction zone where two of Earth's tectonic plates collide and one dives into the mantle. Some of the most massive eruptions in history came from arc volcanoes in the Pacific Ocean's "Ring of Fire," which tower above subduction zones.
Ruprecht and co-author Terry Plank are now analyzing olivine crystals from other arc volcanoes — including those in Alaska's Aleutian Islands, Chile and Tonga — for signs of fast-rising magma. "It's clearly in every arc we've looked in. [But] in terms of an arc setting, I don't think every second volcano will have it. It will be fewer than that," Ruprecht said. Looking at more volcanoes will also help researchers understand why some melts are rabbit-quick, while others rise like tortoises.
But most monitoring systems are laid out to look at shallow depths (6 miles, or 10 km), where magma and hot fluids force their way upward before an eruption, so new networks would have to be built to monitor the deeper goings-on. (These systems currently provide weeks to months of warning before an eruption.) And volcanologists would need to figure out how to predict eruptions from deep earthquakes without too many false alarms.
"Perhaps at volcanoes like Irazú and others like it, you could focus part of your efforts on looking for these deep signatures and know that in at least a year, you could expect an eruption," Kent said. "That's pretty useful from a hazards evaluation standpoint, but trying to figure out when a volcano might next erupt is a very risky game and very difficult to do."
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