NATION IN BRIEF : ALASKA : Redoubt Volcano Unleashes Rockslide

Part of the summit lava dome on Redoubt Volcano collapsed, sending up a plume of ash and unleashing a rockslide down a flank of the mountain near two scientists, the Alaska Volcano Observatory said. There was no telltale seismic increase before the lava dome collapsed and the mountain ejected a plume of ash and steam that reached 31,000 feet. Small, shallow earthquakes, which have been occurring at Redoubt since it came to life Dec. 14, 1989, usually increase in magnitude and frequency before an eruption as a warning signal. The 10,197-foot mountain 110 miles southwest of Anchorage sent the rockslide roaring down from the summit crater on the north flank of the mountain to about 1,000 feet short of where the U.S. Geological Survey scientists were working. They were unharmed, officials said. Redoubt has been erupting roughly once a week for several months.