YELLOW: Volcano is exhibiting signs of elevated unrest above known background level or, after a change from a higher level, volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.
Alaska's restless geology continues: on Friday, scientists raised the alert level at Iliamna volcano -- 130 miles southwest of Anchorage on the lower west side of the Kenai Peninsula -- to "advisory" after a period of continued increasing seismicity led them to believe that the volcano may be mounting for an eruption.
Scientists on Wednesday put out an alert that the volcano had seen three months of increasing temblors, which they said might be caused by increased magma formation, but it wasn't enough to raise the volcano's alert level. That changed Friday, and comes as the number and level of quakes "now exceeds normal background levels," according to the Alaska Volcano Observatory.
The "advisory" warning of yellow means that the volcano is experiencing unusual activity, but hasn't explicitly erupted. Kanaga volcano in the Aleutians had a minor eruption back in February that launched a small ash cloud and prompted a similar advisory.
Meanwhile, a minor eruption was detected Thursday at the regularly-active Cleveland volcano in the Aleutians, but satellite data wasn't available to determine if there was any ash emission. Scientists continue to monitor both volcanoes. Read More