Dotsero volcano may erupt |

Dotsero volcano may erupt

Donna GrayPost Independent Staff

Four thousand years ago, a volcano erupted and left a mark that’s barely visible today. But the Dotsero volcano, now a pile of ash and reddened soil on the east end of Glenwood Canyon north of Interstate 70 and the Eagle River, has appeared on the radar screen of the U.S. Geological Survey, which recently rated the threats of volcanoes across the country.”This is the first comprehensive report on volcanoes since Mount St. Helens” erupted 25 years ago, said Clarice Ransom, spokesman for the USGS in Reston, Va.Dotsero is rated as a moderate threat for its potential to spew volcanic ash into the air at such altitudes that it could disrupt airplane traffic. Sunset Crater in Arizona is also a moderate threat. “Where you sit in Colorado, that part of the U.S. is heavily trafficked by jet airplanes,” said Jim Quick, USGS program coordinator for volcanic hazards. “If Dotsero should erupt with an explosive event, it would put ash up to flight altitudes and threaten aircraft.” Quick explained that the USGS evaluated volcanoes in the United States as well as its territories, and scientists believe any volcano that has erupted in the last 10,000 years, during the geologic Holocene Era, could become active again. The report identified a handful that are not well-monitored but could present a danger. Four are currently erupting: Mount St. Helens; Anatahan, in the Marianas Islands of the western Pacific; Mount Spurr, in Alaska; and Kilauea, in Hawaii. Thirteen were rated as very high threats, including nine in the Cascade Mountains and four in Alaska, and 19 were identified as having a high potential to disrupt airplane flights with volcanic ash, primarily in Alaska and the Marianas. Another 21 volcanoes need individual monitoring, including the Yellowstone caldera, which underlies most of Yellowstone National Park, the report said.Dotsero is not one of those, however. The volcano is not likely to erupt in our lifetime.”The probability of it happening in a human lifetime is pretty low,” Quick said. “But at some time in future? That’s harder to judge, especially in the absence of monitoring.””In terms of your and children’s lifetimes, I wouldn’t worry too much” about Dotsero, Quick added.Quick explained that Dotsero is a “maar,” or explosive volcano.”Because it’s a maar it ended up with a moderate threat rating. Because it has erupted we feel it could happen again,” he said.Dotsero also produced “lahars,” mudflows of water and volcanic ash that traveled about one and a half miles downstream of the volcano and diverted the flow of the Eagle River to the south side of the valley.”(They) can be quite devastating downstream,” Quick said. Such lahars, or mudflows, from the eruption of Mount St. Helens 25 years ago dammed a river and resulted in extensive damage to buildings.”They have the density and viscosity of wet concrete,” Quick said of the mudflows.Volcanic flow from the Dotsero crater was cut by I-70 and is visible on the south side of the highway. The crater itself is north of the interstate, above the trailer park.Contact Donna Gray: 945-8515, ext.

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