On 11 October AVO reported that satellite data of Semisopochnoi indicated partial erosion of a tephra cone in the crater of Cerberus?s N cone.
A crater lake about 90 m in diameter filled the vent.
The data also suggested that the vent had not erupted since 1 October.
Seismicity remained elevated and above background levels.
The next day AVO lowered the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory, noting the recent satellite data results and lack of tremor recorded during the previous week.
Source: US Geological Survey Alaska Volcano Observatory (AVO)