Alaska Volcano Hints At Eruption

View north of Crater Peak, the active vent of Mount Spurr, Alaska, on 26 September 1992. Crater Peak erupted in June, August, and September 1992. Ash from the August eruption closed Anchorage International Airport. Behind the small steam plume is Mount Spurr. Spurr and the peak visible on the left define the rim of caldera, evacuated by a huge debris avalanche about 10,000 years ago.
U.S. Geological Survey
Noting a swarm of tiny earthquakes beneath volcanic Mount Spurr, scientists have warned that the volcano 80 miles west of Anchorage could erupt in the next few weeks.

Eruptions most often follow a pattern of quakes, said geophysicist John Power of the U.S. Geological Survey, one of three federal and state partners in the Anchorage-based Alaska Volcano Observatory.

Power added, however, that the earthquakes will most likely end without an eruption.

Mount Spurr was last significantly active in 1992. In an August explosion that year, it spread a thin layer of ash over Anchorage.

The mountain's recent activity began slowly in February and intensified July 4, the observatory said this week. An average of 20 small quakes are now occurring daily, a rate higher than at any time since 1992.

The temblors occur as deep as four miles below the surface. The largest recent quake was on July 12 and measured 1.4 in magnitude.

Mount Spurr is one of more than 40 active Alaska volcanoes.