The U.S. Geological Survey issued
an an orange alert Thursday for Cleveland Volcano in the Aleutian Islands.
According to the U.S. Geological Survey, an orange alert means:
"[A] Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, time frame uncertain, OR eruption is underway with no or minor volcanic-ash emissions [ash-plume height specified, if possible]."
The orange alert is the third-highest of four possible levels on the USGS volcano scale.
"Satellite data indicate that this is a single explosion event, however, more sudden explosions producing ash could occur with plumes exceeding 20,000 feet above sea level. Such explosions and their associated ash clouds may go undetected in satellite imagery for hours."
The volcano has shown signs of erupting in the past.
, "A similar alert had been issued in early September, amid concerns that the volcano could be leaking from its flanks if the lava inside continued to build up."
At this time, there is no timetable to when the volcano may erupt.
It's last eruption was back in February 2001. Smaller eruptions took place in January and in June 2009, CNN reports
Alaska's Cleveland volcano is 940 miles southwest of Anchorage.