Significant explosive eruption at Bogoslof, ash to 9.1 km (30 000 feet) a.s.l.


A significant explosive eruption began at Bogoslof volcano at 11:17 UTC on June 27, 2017 and lasted roughly 14 minutes. The eruption prompted the Alaska Volcano Observatory (AVO) to raise the Aviation Color Code to Red.

The eruption produced a volcanic cloud that reached an altitude of 9.1 km (30 000 feet) above sea level based on satellite data. No infrasound was detected at networks from nearby islands, but the World Wide Lightning Location Network (WWLLN) detected lightning strokes associated with the resulting volcanic cloud.

The volcanic cloud remains visible in satellite data moving northeast and is not expected to impact local communities or mainland Alaska.

Seismicity has since declined to background levels, but Bogoslof volcano remains at a heightened state of unrest and in an unpredictable condition.

This morning’s explosion occurred less than 12 hours after a similar explosion yesterday afternoon, and recent eruptive episodes have produced multiple short-duration explosions with pauses of minutes to hours. Additional explosions producing high-altitude volcanic clouds could occur at any time. AVO will continue to monitor seismic and infrasound data from nearby islands, as well as lightning data from the World Wide Lightning Location Network for signs of renewed activity. 

The Aviation Color Code remains Red and Volcano Alert Level Warning

Geological summary

Bogoslof is the emergent summit of a submarine volcano that lies 40 km (24.8 miles) north of the main Aleutian arc. It rises 1 500 m (4 920 feet) 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 (0.46 x 1.2 miles) 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 (1 970 feet) NW of Bogoslof Island, is a remnant of a lava dome that was formed in 1883. (GVP)

Featured image: Bogoslof seen from Alaska Airlines flight from Adak to Anchorage on June 22, 2017. Credit: Cyrus Read / AVO/USGS


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One Comment

  1. Been observing Bogoslof for several months and as volcanos go this one is a strange anomaly. Most eruptions go silent after a short period of time. Ironically, the Sheveluch volcano erupted within two hours of Bogosloff on the 27th of June. This is either a precursor of a big event or maybe a coincidence. We should stay alert. (I’ll keep my own ideas to myself) What do you all think???

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