Ksudach Volcano | John Seach


(Voniuchi Khrebet, Vonyuchy Khrebet, Kskhudach, Stubel)

Kamchatka, Russia

51.80 N, 157.53 E
summit elevation 1079 m
shield volcano

Ksudach volcano is located in southern Kamchatka. The summit contains two lakes - Balshoe and Kraternoe. The volcano consists of nested calderas which formed during five collapse events. Two larger calderas  formed in the Late Pleistocene time and three smaller ones during the Holocene.

Pyroclastic deposits of the largest Holocene eruptions are tens to hundreds of meters thick near the vent.

During the last 10,000 years, five catastrophic explosive caldera-forming eruptions took place in Kamchatka. Three occurred at Ksudach volcano and two were associated with the formation of the Karymsky and Kurile Lake-Iliinsky calderas.

1907 Eruption
Ksudach volcano erupted on 28th March 1907. The eruption destroyed Shtyubel Volcano, leaving a tuff cone with a 1.5 km in diameter horseshoe-shaped crater filled with a deep lake. Ash fell 200 km from the volcano. The eruption produced 2.4 cubic km of tephra. The 1907 eruption was one of the major blast events of the 20th century, and produced a major Plinian column with widespread ash deposits.

The eruption at Ksudach volcano can be divided into four phases. The first phase opened the vent and produced pyroclastic fallout. The second phase was a plinian eruption. The third phase involved a powerful directed blast towards the NNE. The fourth phase at Ksudach consisted of shallow hydromagmatic eruptions
that produced five pyroclastic surge deposits with ash cloud surge beds to the west-northwest.

Major eruptions in the Kamchatka have a disproportional effect on global climate, due to the low troposphere elevation at these latitudes, and the ease of dispersal of ash, aerosol, and gas.

240 AD Eruption
A caldera-forming eruption occurred at Ksudach volcano in 240 AD. This was the largest historical event in the Kamchatka peninsula. The explosive eruption was similar in size to the 1883 eruption of Krakatau in Indonesia. The eruption ejected 19 cubic km of material (8 cubic km DRE). Tephra fall reached 1000 km north of the volcano, and eruption column was estimated to reach 30 km high. The eruption produced a 4 x 6.5 km wide caldera.

Further reading
Volynets, O. N., et al. "Holocene eruptive history of Ksudach volcanic massif, South Kamchatka: evolution of a large magmatic chamber." Journal of Volcanology and Geothermal Research 91.1 (1999): 23-42.

Grishin, Sergei Yu, et al. "Succession following the catastrophic eruption of Ksudach volcano (Kamchatka, 1907)." Vegetatio 127.2 (1996): 129-153.

Braitseva, O. A., et al. "The caldera-forming eruption of Ksudach volcano about cal. AD 240: the greatest explosive event of our era in Kamchatka, Russia." Journal of Volcanology and Geothermal Research 70.1-2 (1996): 49-65.

Ksudach Volcano Eruptions

1907, 240 AD, 5000 BC, 7900 BC.