Mount Redoubt volcano in Alaska expected to erupt 'within days'

Alaska’s known for dramatic scenery. That scenery is there because of very active geology.
Mount Redoubt, a volcano 100 miles southwest of Anchorage, is rumbling and simmering, prompting geologists to warn that an eruption may be imminent.

Mt. Redoubt, a 10,197-foot active volcano 103 miles west of Anchorage. Scientists at the US Geological Survey’s Alaska Volcano Observatory (AVO) are keeping close tabs on the mountain. They say an eruption may be imminent.

On Thursday, the observatory said: "Seismicity remains above background and largely unchanged with several volcanic earthquakes occurring every hour."

Last fall, it showed signs that it may be waking up after a decade’s slumber. Since Jan. 23, that activity has been rising — largely marked by an increase in tremors recorded by seismic sensors near the summit.According scientists to the AVO, the first tip that the mountain might be clearing its throat again came via peoples’ noses. Toward the end of last September, residents downwind of the volcano reported the pungent rotten-egg smell of hydrogen sulfide. The AVO ordered up some overflights of the mountain. Sure enough, scientists detected higher-than-usual levels of carbon dioxide, sulfur dioxide, and hydrogen sulfide.

The difference is gas trying to escape gets blocked, possibly by a lava dome or a viscous magma that increases the power from beneath, said observatory geologist Jennifer Adleman.

"Its pressure keeps building and building," she said.

The last time the 10,197-foot peak blew was during a five-month stretch starting in December 1989. It disrupted international air traffic and placed a layer of volcanic dust throughout the Anchorage area.

Scientists at the Alaska Volcano Observatory have been watching it since the weekend. And so, it turns out, has the public. Two webcams have been set up to monitor the mountain. And in a particularly Web-savvy touch, observatory staff are sending out updates on Twitter.

Volcanoes in Alaska, including Redoubt, typically erupt explosively, shooting ash almost eight miles high. Volcanic ash features small, jagged pieces of rock and glass.
This differs from volcanoes in Hawaii, which usually have slow rolling lava ooze out.