High-level eruption at Bezymianny volcano, Aviation Color Code raised to Red, Russia

A strong explosive eruption occurred at Russia’s Bezymianny volcano at 05:38 UTC on April 7, 2023. As a result, the Aviation Color Code was raised to Red.

According to the Tokyo VAAC and KVERT, video and satellite data show an ash plume rising up to 12 km (40 000 feet) a.s.l., drifting SE of the volcano.¹

Activity at the volcano intensified on March 29 with a series of eruptions ejecting ash up to 6 km (20 000 feet) a.s.l., drifting E, and further on April 2, when ash plumes rose to 4.3 km (14 000 feet) a.s.l., drifting SE.

Ash explosions up to 10 – 15 km (32 800 – 49 200 ft) a.s.l. could occur during the next several days, KVERT said. Ongoing activity could affect international and low-flying aircraft.

Geological summary

Prior to its noted 1955 – 56 eruption, Bezymianny had been considered extinct. The modern volcano, much smaller in size than its massive neighbors Kamen and Kliuchevskoi, was formed about 4 700 years ago over a late-Pleistocene lava-dome complex and an ancestral edifice built about 11 000 – 7 000 years ago.

Three periods of intensified activity have occurred during the past 3 000 years.

The latest period, which was preceded by a 1 000-year quiescence, began with the dramatic 1955/56 eruption. This eruption, similar to that of St. Helens in 1980, produced a large horseshoe-shaped crater that was formed by the collapse of the summit and an associated lateral blast.

Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater.²

References:

¹ VONA/KVERT Information Release for Bezymianny volcano – KVERT, Institute of Volcanology and Seismology FEB RAS – April 7, 2023

² Bezymianny – Geological summary – GVP

Featured image: Ash plume rising from Bezymianny volcano at 06:10 UTC on April 7, 2023. Credit: JMA/Himawari-9, Zoom Earth, The Watchers