Sheveluch exhibiting heightened unrest - lava domes growing, hot avalanches and fumarole activity

Sheveluch exhibiting heightened unrest - lava domes growing, hot avalanches and fumarole activity

The extrusive activity of the Sheveluch volcano in Kamchatka, Russia, shows signs of increasing, and some avalanches create several kilometers long pyroclastic flows and up to 5.1 km (17 000 feet) high ash plumes.

The SW sector of the lava dome continues to produce almost constant small to moderate glowing avalanches, Volcano Discovery reported.

On February 29, 2016, KVERT reported the lava domes continue to grow, accompanied by hot avalanches, fumarole activity, and incandescence of the dome summit. Satellite data also indicates a thermal anomaly over the volcano. The Aviation Color Code remains orange, signalizing the volcano exhibits heightened unrest with increased likelihood of eruption.

Incandescent rockfalls from Sheveluch, February 29, 2016. Image credit: KVERT & Weathernews Inc

Small pyroclastic flow into the SW corridor of the active lava dome. Image credit: KVERT

According to Tokyo VAAC, the volcano erupted on February 24. An eruption plume rose approximately 6.4 km (21 000 feet) in altitude and drifted northwest at a speed of 46.3 km/h (28.8 mph), as indicated by the satellite data.

In the period between February 12 and 19, lava-dome extrusions onto Sheveluch's N flank was also accompanied by fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Explosions on February 18 generated ash plumes that drifted NW, according to GVP. Satellite images detected a daily and intense thermal anomaly over the dome, and the Aviation Color Code remained at Orange.

Geological summary

The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 cu km (312 cu miles) volcano is one of Kamchatka's largest and most active volcanic structures. The summit of roughly 65 000-year-old Stary Shiveluch is truncated by a broad 9 km (5.6 miles) wide late-Pleistocene caldera breached to the south. Many lava domes dot its outer flanks. The Molodoy Shiveluch lava-dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch.

At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera. (GVP)

Featured image: Small pyroclastic flow into the SW corridor of the active lava dome. Image credit: KVERT

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