On 2 January AVO lowered the Volcano Alert Level for Shishaldin to Advisory (the second level on a four-level scale) and the Aviation Color Code to Yellow (the second color on a four-color scale), noting that activity had declined over the past two months since the last significant explosive event on 3 November. Small explosions continued to be periodically detected in infrasound data, though no new deposits inside or outside the crater had recently been observed. Surface temperatures detected in satellite data were low, suggesting that no fresh lava was present in the summit crater. Steaming from the crater continued to be observed in webcam images.

Geological Summary. The symmetrical glacier-covered Shishaldin in the Aleutian Islands is the westernmost of three large stratovolcanoes in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." Constructed atop an older glacially dissected edifice, it is largely basaltic in composition. Remnants of an older edifice are exposed on the W and NE sides at 1,500-1,800 m elevation. There are over two dozen pyroclastic cones on its NW flank, which is covered by massive aa lava flows. Frequent explosive activity, primarily consisting of Strombolian ash eruptions from the small summit crater, but sometimes producing lava flows, has been recorded since the 18th century. A steam plume often rises from the summit crater.

Source: US Geological Survey Alaska Volcano Observatory (AVO)