USGS upgrades Aleutian volcano alert level

Megan Edge

March 25, 2015

Semisopochnoi Island is shown in this November 2012 photo. The USGS upgraded the island's volcano alert level status to "advisory" and its aviation code to "yellow" Wednesday after an increase in seismic activity. Roger Clifford

Citing increased seismic intensity, the U.S. Geological Survey is upgrading the volcano alert level status for Semisopochnoi, an Aleutian Island volcano, to "advisory," the agency said in a notice issued Wednesday morning.

Seismic activity at the Semisopochnoi volcano began in January, but "has increased in intensity over the past few days," USGS wrote in the notice. "In addition, we have detected brief periods of seismic tremor, which can indicate movement of magma or magmatic gases."

Semisopochnoi is remote even by Alaska standards. It lies on an island of the same name some 127 miles from Adak and 1,283 miles from Anchorage.

The volcano last erupted in 1987.

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