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Report on Bogoslof (United States) — 20 September-26 September 2017


Bogoslof

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 20 September-26 September 2017
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2017. Report on Bogoslof (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 20 September-26 September 2017. Smithsonian Institution and US Geological Survey.

Weekly Report (20 September-26 September 2017)

Bogoslof

United States

53.93°N, 168.03°W; summit elev. 150 m

All times are local (unless otherwise noted)


AVO reported that during 20-26 September nothing significant was observed in partly to mostly cloudy satellite images of Bogoslof, and no activity was detected in seismic or infrasound data. Weakly elevated surface temperatures were identified in satellite images during 22-23 September, indicating ongoing unrest. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

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)