Sunday, September 18, 2005

Crater Lake is monitored the least

Crater Lake may be Oregon’s only national park, but it receives the least monitoring for possible eruptions among the state’s five most active volcanoes, partly because it lies so far from population centers.“Crater Lake is the worst-case scenario,” said seismologist Seth Moran of the U.S. Cascades Volcano Observatory in Vancouver, Wash.

“Mount Saint Helens taught us that we need a decent network of seismic monitors or else we might miss the subtle signs (of volcanism). Once they wake up, they’re too hot to get close to.”Although there is a network of seismic monitors up and down the Cascades, the nearest one to Crater Lake is 29 miles away.“In every (other) case, volcanoes have a monitor within five miles, but Crater Lake is a remote volcano, not near any town and it hasn’t erupted very recently,” Moran said.

“To be frank, resources are limited, so we have to concentrate on the most likely ones: Rainier (near Seattle), Hood (near Portland) and South Sister (near Bend).”Geologists say the five Oregon volcanoes most likely to become active are Hood, Jefferson, South Sister, Newberry and Crater Lake.Moran said money is lacking for more personnel and for purchase and maintenance of equipment that would form part of the monitoring network.Crater Lake blew violently only 7,500 years ago, and Wizard Island, the volcanic cone within the caldera that holds the lake, blew only 5,000 years ago.

The eruptions was among the most spectacular volcanic events in local human memory, and left a huge caldera that filled with rain and snowmelt and is now among the purest natural water on earth. The event is recalled in the mythology of the Klamath Indians whose territory was hit by lava and ash.Since then, said park historian Steve Mark, there have been only hints of the volcano’s power, like the gaseous clouds emerging from the waters through the summer of 1945 and magma-caused earthquakes up to 6.0 magnitude at nearby Mountain Lakes Wilderness Area in 1993.Although Crater Lake is called “the sleeping giant,” “we haven’t had any indication that Crater Lake is active,” said Mac Brock, chief of natural resources for the park.

“A volcanic eruption is really highly unlikely. It’s not considered an area of concern like Mount Rainier.”But that doesn’t mean that a Crater Lake eruption won’t happen someday, Mark said.Ten-thousand years from now, Mark said, “it wouldn’t surprise me if (it) had erupted. Crater Lake is due to rebuild itself in time.”

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