Report on Bogoslof (United States) — 12 April-18 April 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 12 April-18 April 2017
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2017. Report on Bogoslof (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 12 April-18 April 2017. Smithsonian Institution and US Geological Survey.
53.93°N, 168.03°W; summit elev. 150 m
All times are local (unless otherwise noted)
Increased seismicity at Bogoslof was recorded by stations on nearby islands starting around 1501 on 15 April, prompting AVO to raise the Aviation Color Code to Orange and the Volcano Alert Level to Watch. The seismic activity subsided a few hours later; there was no evidence of renewed eruptive activity from infrasound, lightning, or satellite data during 15-18 April.
Geologic Background. Bogoslof is the emergent summit of a submarine volcano that lies 40 km north of the main Aleutian arc. It rises 1500 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 of 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. Fire Island (New Bogoslof), a small island located about 600 m NW of Bogoslof Island, is a remnant of a lava dome that was formed in 1883.