AVO reported that seismicity at Bogoslof had declined during the previous three weeks to background levels and the last moderate earthquake, a M 2.7, was recorded on 9 November. No other signs of unrest were detected. Both the Volcano Alert Level and the Aviation Color Code were changed to Unassigned on 24 November. A seismic swarm had started around 22 October and was characterized by 5-10 events per hour and a total of around 1,100 earthquakes per week at the peak. The volcano was monitored by a single local seismic station, distant seismic and infrasound instruments, satellite data, and lightning networks.

Geological Summary. Bogoslof is the emergent summit of a submarine volcano that lies 40 km N of the main Aleutian arc. It rises 1,500 m above the Bering Sea floor. Repeated construction and destruction of lava domes at different locations during historical time has greatly modified the appearance of this "Jack-in-the-Box" volcano and has introduced a confusing nomenclature applied during frequent visits by exploring expeditions. The present triangular-shaped, 0.75 x 2 km island consists of remnants of lava domes emplaced from 1796 to 1992. Castle Rock (Old Bogoslof) is a steep-sided pinnacle that is a remnant of a spine from the 1796 eruption. The small Fire Island (New Bogoslof), about 600 m NW of Bogoslof Island, is a remnant of a lava dome formed in 1883.

Source: US Geological Survey Alaska Volcano Observatory (AVO)