Alaska's Mount Redoubt is puffing a steam plume out several hundred feet above the volcano's crater, but still hasn't erupted.

Volcanologist Dave Schneider at the Alaska Volcano Observatory says the activity Monday is largely due to atmospheric conditions, such as winds and humidity, that make steam more visible.

Stephanie Prejean, a seismologist at the observatory, says Redoubt's ongoing earthquakes have shifted in recent days to a higher frequency, which could signify actual rock breaking.

Prejean says Redoubt continues to emit large quantities of volcanic gas, indicating the presence of new magma in the earth's crust.

The observatory in late January began detecting a sharp increase in earthquakes beneath the mountain about 100 miles southwest of Anchorage.

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