OPALA VOLCANO BY STEPAN KRASCHENINNIKOW

STEPAN  KRASCHENINNIKOW (1711-1755)
Opala volcano (2,475m-8100 ft)
Russia (Kamchatka)

 In Mountains of Kamtschatka, St Petersbourg 1755

The volcano
Opala (Опала)  (2,475m-8100 ft)  is a large stratovolcano located in South Kamchatka about 50 km west of the Eastern volcanic front.  The volcano sits on the northern rim of a 14x12 km large Late Pleistocene caldera. The summit of the volcano has a nice small crater. The most prominent feature at the foot of the volcano is Baranii Amphitheater - a large Novarupta-type crater filled with extrusive domes. This crater formed about 1500 years BP and produced 9-10 km3 of rhyolitic pumice that is about 4.5 km3 of magma. Later the crater was filled with extrusive domes. There was at least one later eruption within the crater, which formed explosive craters on the surface of the extrusive domes and produced minor pumiceous tephra.  Several hazy reports of Opala's historical eruptions were known, but no real evidence of recent eruptions had been found at the slopes of the volcano.  However,  later studies have allowed to document a significant explosive eruption from the summit crater, which occurred as recently as about 300 years ago and produced rhyolitic tephra (informally known as "Ghost layer"). Earlier eruptions from Opala produced lava flows and pumiceous tephra.  The eruption from Baranii  Amphitheater was one of the most voluminous explosive eruptions in Kamchatka during the Holocene.  Opala is undoubtedly an active volcano posing a serious hazard to the region.  Recent eruptions from Opala produced dominantly rhyolitic material that indicates a presence of living silicic chamber under the volcano. Holocene products of Opala volcano are high potassic andesites-rhyolites. Baranii Amphitheater crater produced uniform rhyolites without any admixture of more mafic varieties.  Opala volcano has been producing andesitic-dacitic lavas and tephras for most of Holocene; the last significant eruption of this kind was ab. 3500 14C yrs BP.  How was it possible to produce, accumulate, store and finally erupt - just in a couple of millenia - about 4.3 km3 of rhyolitic magma from the crater located on the volcano's slope, a mere 5 km from its summit? Was the OP eruptionit a part of the Opala volcano story or any special event? Why is this magma so similar to Chasha crater's one, stored 15 km away? These are genral questions to this volcano.

The artist 
Stepan Petrovich Krasheninnikov (Степа́н Петро́вич Крашени́нников) was a Russian explorer of Siberia, naturalist and geographer who gave the first full description of Kamchatka in the early 18th century. He was elected to the Russian Academy of Sciences in 1745. The Krasheninnikov Volcano on Kamchatka is named in his honour. He embarked upon the Second Kamchatka Expedition (1731–42). Krasheninnikov was to study plants, animals and minerals, but in addition he developed a strong interest in Siberian history and geography. During the early part of the expedition, he accompanied professor Gmelin on the travel through the Urals and western Siberia to Yeniseysk. He made numerous observations of natural history, ethnology and linguistics, e.g. records of Evenki (tungus) and Buryat vocabulary. From Bering’s headquarters at Yakutsk, the expedition professors Gmelin and Gerhard Friedrich Müller sent Krasheninnikov ahead to Okhotsk and Kamchatka to build house and make preliminary observations. Thus, he became the member of the expedition with the most extensive knowledge of the peninsula. He published his observations in 1755 (Описание земли Камчатки); English translation by James Grieve (1764) as History of Kamtschatka. However, he drew extensively on the manuscripts of the deceased Georg Wilhelm Steller. Apart from detailed accounts of the plants and animals of the region, there also were reports on the language and culture of the indigenous Itelmen and Koryak peoples, with whom he is said to have got along extremely well. Krasheninnikov spent ten years on the Second Kamchatka Expedition. On his return to St Petersburg, he wrote and defended his doctoral thesis on ichthyology in 1745. He was appointed adjunct at the Academy of Sciences, and later head of the Academy's Botanic Garden and professor of natural history at the university. He was one of only 26 Russians to become Academy members in the 18th century. In 1752, Krasheninnikov went on his last expedition to the tracts of Lake Ladoga and Novgorod to investigate the flora. He died before being able to publish his observations, which instead were published by David de Gorter.