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Geologists redraw map of volcanic history in Southeast Alaska

Volcanic vents and cinder cones in Behm Canal in Southeast Alaska.
JAMES BAICHTAL, U.S. Forest Service

Geologists with the U.S. Forest Service and the U.S. Geological Survey have spent recent years taking a close look at the volcanic history of Southeast Alaska and have added a dozen volcanoes to the map, as well as reclassifying many already known volcanic vents and lava flows. But residents of the area need not worry -- it's unlikely anything in Southeast is going to erupt soon, reports LiveScience.

Sprinkled across hundreds of islands and fjords, most of the volcanic piles are tiny cones compared to the super-duper stratovolcanoes that parade off to the west, in the Aleutian Range.

But the Southeast's volcanoes are in a class by themselves, the researchers found. A chemical signature in the lava flows links them to a massive volcanic field in Canada. Unusual patterns in the lava also point to eruptions under, over and alongside glaciers, which could help scientists pinpoint the size of Alaska's mountain glaciers during past climate swings.

The scientists' work included ocean dives in submersibles to document previously unknown volcanic features. 

Some of the unusual finds ... include a maar lying 295 feet underwater near Cape Addington, about 40 miles west of Craig. Maars are bomblike craters blasted out when magma rising underground hits groundwater and explodes. 

Read more at LiveScience: A blast of a find: 12 new Alaskan volcanoes. The article is accompanied by an image gallery.



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