Semisopochnoi Volcano

Courtesy of the Alaska Volcano Observatory

Scientists have downgraded the alert level for an Aleutian volcano that began showing an increase in signs of eruption and emitting harmful ash late last week. 

According to Dave Schneider, a geophysicist with the Alaska Volcano Observatory, over the last several weeks, satellites and pressure sensor data revealed ramped up activity at Semisopochnoi Volcano, which is located on an uninhabited island in the Rat Islands about 600 miles southwest of Unalaska. 

Courtesy of William Dushkin

Scientists have upgraded the alert level at one of Alaska's most active volcanoes after increased volcanic unrest.

Starting last week, satellites detected an increase of gas emissions and elevated surface temperatures at Cleveland Volcano, which is located on an uninhabited island in the central Aleutians, west of Umnak Island.

The data indicates a potential for increased eruptions, according to Dave Schneider, a geophysicist with the Alaska Volcano Observatory, so the AVO has raised the aviation color code to "yellow" and the alert level to "advisory."