Zavaritski Caldera
| Zavaritski Caldera | |
|---|---|
 | |
| Highest point | |
| Elevation | 624 m (2,047 ft) |
| Coordinates | 46°55′N 151°57′E / 46.917°N 151.950°E |
| Geography | |
  Zavaritski Caldera Zavaritski Caldera in Russian Far East | |
 | |
| Location | Simushir, Kuril Islands, Russia |
| Geology | |
| Mountain type | Caldera |
| Last eruption | November to December 1957 |
Zavaritski Caldera (Russian: Вулкан Заварицкого, Vulkan Zavaritskogo), also spelled "Zavaritskii" and "Zavaritsky", is a caldera system located in the centre of Simushir Island, in the central Kuril Islands, Russia. The volcano is named after Alexander Nikolayevich Zavaritski, a scientist of the Academy of Sciences of the Soviet Union.
Geology
[edit]The Zavaritski volcano contains three nested calderas, measuring 3km, 8km and 10km in diameter. The youngest caldera, which is partially filled by Lake Biryuzovoe, was formed during the Holocene and features several young volcanic cones and lava domes. The lake surface sits at an elevation of 40m above sea level with the lake bottom at 30m below sea level. Lake sediments overlying pumice deposits indicate that a previous caldera lake surface existed 200m above sea level.
The last reported explosive eruption was recorded in November 1957. This destroyed a 500m diameter cone[1] that reportedly grew pre-eruption and had formed a peninsula extending into the lake from the north east caldera wall. The eruption filled the north west section of the lake including the emplacement of a 350m wide, 40m high dome.
1831 eruption
[edit]Research indicates that Zavaritski Caldera may have been the source of a high magnitude, explosive eruption that occurred in the summer of 1831.[2]
The eruption is evidenced by sulfate peaks in polar ice cores and from historical observations of atmospheric phenomena across the Northern Hemisphere (such as observations of a blue, purple and green sun).
It is thought that the mass injection of sulfur from the eruption caused Northern Hemisphere climate cooling of 0.5–1.0°C, coincided with fluctuations in the Indian and African monsoons, and preceded major famines (including the Guntur famine of 1832 and Kyōhō famine). However, the source of this major eruption has remained a mystery.
The researchers, led by volcanologist William Hutchison, conducted geochemical analyses of several Greenland ice cores. They found coinciding with the sulphate peaks from the 1831 eruption, microscopic layers of tephra that chemically matched deposits from the most recent Plinian Zavaritski eruption that were dated to the early 19th century. Modelling suggests that the eruption could have been a 5–6 magnitude eruption event and the reconstructed radiative forcing of Zavaritski is comparable to the 1991 eruption of Mount Pinatubo and could account for the climate cooling observed between 1831–1833.
See also
[edit]References
[edit]- ^ Gorshkov, G S (1958). Catalog of Active Volcanoes of the World and Solfatara Fields (7 ed.). Rome IAVCEI: International Volcanological Association. pp. 1–99.
- ^ Hutchison, William; Sugden, Patrick; Burke, Andrea; Abbott, Peter; Ponomareva, Vera V.; Dirksen, Oleg; Portnyagin, Maxim V.; MacInnes, Breanyn; Bourgeois, Joanne; Fitzhugh, Ben; Verkerk, Magali; Aubry, Thomas J.; Engwell, Samantha L.; Svensson, Anders; Chellman, Nathan J.; McConnell, Joseph R.; Davies, Siwan; Sigl, Michael; Plunkett, Gill (7 January 2025). "The 1831 CE mystery eruption identified as Zavaritskii caldera, Simushir Island (Kurils)". Proceedings of the National Academy of Sciences. 122 (1): e2416699122. doi:10.1073/pnas.2416699122. Retrieved 5 January 2025.
External links
[edit]- "Zavaritzki Caldera". Global Volcanism Program. Smithsonian Institution.
- Aerial image retrieve from NASA Technical Reports Server on 19 April 2007.
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