Large debris avalanches and associated eruptions in the Holocene eruptive history of Shiveluch Volcano, Kamchatka, Russia

Abstract

Shiveluch Volcano, located in the Central Kamchatka Depression, has experienced multiple flank failures during its lifetime, most recently in 1964. The overlapping deposits of at least 13 large Holocene debris avalanches cover an area of approximately 200 km 2 of the southern sector of the volcano. Deposits of two debris avalanches associated with flank extrusive domes are, in addition, located on its western slope. The maximum travel distance of individual Holocene avalanches exceeds 20 km, and their volumes reach F3 km 3 . The deposits of most avalanches typically have a hummocky surface, are poorly sorted and graded, and contain angular heterogeneous rock fragments of various sizes surrounded by coarse to fine matrix. The deposits differ in color, indicating different sources on the edifice. Tephrochronological and radiocarbon dating of the avalanches shows that the first large Holocene avalanches were emplaced approximately 4530-4350 BC. From F2490 BC at least 13 avalanches occurred after intervals of 30-900 years. Six large avalanches were emplaced between 120 and 970 AD, with recurrence intervals of 30-340 years. All the debris avalanches were followed by eruptions that produced various types of pyroclastic deposits. Features of some surge deposits suggest that they might have originated as a result of directed blasts triggered by rockslides. Most avalanche deposits are composed of fresh andesitic rocks of extrusive domes, so the avalanches might have resulted from the high magma supply rate and the repetitive formation of the domes. No trace of the 1854 summit failure mentioned in historical records has been found beyond 8 km from the crater; perhaps witnesses exaggerated or misinterpreted the events.

Sector collapses and large landslides on Late Pleistocene–Holocene volcanoes in Kamchatka, Russia

“…4B, C; Table 1; Ponomareva et al, 1998). All Holocene collapses were followed by explosive eruptions, however, the largest plinian eruptions of Shiveluch were not associated with debris avalanches (Ponomareva et al, 1998).…”

“…Since then, both events have been reinterpreted as sector collapses and the resulting debris avalanche deposits re-examined (Belousov, 1995;Belousov and Belousova, 1998;Melekestsev, 2006). Other work on the CKD volcanoes includes studies of small-volume historical landslides on Kliuchevskoi (Dvigalo and Melekestsev, 2000), pre-historic collapses of Shiveluch (Ponomareva et al, 1998;Belousov et al, 1999) and brief mention of pre-historic collapses on Kamen', Tolbachik (Melekestsev and Braitseva, 1984), Kharchinsky and Zarechny volcanoes (Volynets et al, 1999). In the rest of Kamchatka, only Avachinsky, Bakening and Mutnovsky debris avalanche and landslide deposits have been documented earlier (Melekestsev and Braitseva, 1984;Melekestsev et al, 1992Melekestsev et al, , 1999 although landslide craters have been identified on 22 volcanoes (Leonov, 1995).…”

“…The volcano consists of the Late Pleistocene stratovolcano (Old Shiveluch), partly destroyed by a 9-km-wide collapse crater, which now encloses an active eruptive center (Young Shiveluch). Shiveluch activity during the Holocene has been characterized by plinian eruptions alternating with periods of dome growth and subsequent debris avalanches (Ponomareva et al, 1998(Ponomareva et al, , 2002.…”

“…The area covered by the 1964 debris avalanche deposits is about 98 km 2 , its volume about 1.5 km 3 , and its travel distance about 16 km (Table 1). A part of the material was displaced as three large toreva blocks which form up to 1.5 km long and 0.15 km high "stairs" immediately south of the collapse crater (Gorshkov and Dubik, 1970;Ponomareva et al, 1998;Belousov et al, 1999). The debris avalanche was not followed by a lateral blast, indicating the absence of a cryptodome in the volcanic edifice (Belousov, 1995).…”

“…4B, C; Table 1; Ponomareva et al, 1998). All Holocene collapses were followed by explosive eruptions, however, the largest plinian eruptions of Shiveluch were not associated with debris avalanches (Ponomareva et al, 1998). The travel distances of individual Holocene avalanches exceed 20 km, and their wide crater, open to the south, formed >10 ka BP (most likely ∼ 30 ka BP) as a result of a sector collapse; deposits of the resulting debris avalanche(s) are seen beyond the boundaries of the Holocene avalanches.…”