Kudach

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Kudach
In the foreground on the left the Ksudatsch (photo from the east from the space shuttle)

In the foreground on the left the Ksudatsch
(photo from the east from the space shuttle )

height 1079  m
location Kamchatka , Russia
Coordinates 51 ° 48 '26 "  N , 157 ° 32' 3"  E Coordinates: 51 ° 48 '26 "  N , 157 ° 32' 3"  E
Kudach (Kamchatka Region)
Kudach
Type Stratovolcano
rock Basalt to andesite
Last eruption 1907
Location of the calderas of the Kudach

Location of the calderas of the Kudach

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The Ksudach ( Russian Ксудач ) is a stratovolcano in the south of the peninsula Kamchatka . Five nested calderas shape the summit of the volcano, which is located in Russia in the Jelisowo district of the Kamchatka region .

location

The Ksudatsch is part of the eastern chain of Kamchatka, a volcanic zone around 700 kilometers long and around 80 kilometers wide, in which almost all active volcanoes on the peninsula are located. The cause of volcanism is a subduction zone in which the Pacific plate plunges under the Eurasian plate . The volcano is located around 150 kilometers south-southwest of Petropavlovsk-Kamchatsky , the capital of Kamchatka.

Build-up and breakouts

The first volcanic eruptions of the Ksudach took place around 40,000 years ago. Eruptions, in which mainly andesite was extracted, started from several eruption centers. The result was a flat volcanic building, described as "shield-like" , made of lava and tephra . Two eruptions in the late Pleistocene caused the summit area of ​​the volcano to collapse, forming calderas I and II. The former has a diameter of 10 to 11 kilometers. Little is known about these two eruptions, as the glaciation of the Ksudatsch in the subsequent glacial period destroyed the associated ash deposits .

In the Holocene the calderas III, IV and V emerged within the two older calderas:

  • Caldera III was formed during an eruption around 7900 BC. BC, where between 1.5 and 2 km³ of tephra was mined. The size of the caldera is estimated to be 2 to 3 kilometers. The eruption of magnitude five on the volcanic explosion index (VEI) was preceded by a phase lasting at least 1000 years in which there were no or only weak eruptions.
  • Two eruptions in quick succession around 5200 and 4900 BC. BC created the Caldera IV with a size of 5 to 6 kilometers. Both eruptions had a VEI magnitude of five; a total of 10 to 11 km³ of tephra were mined. After the collapse of the caldera several emerged lava domes of dacite .
  • Caldera V was formed in an eruption around 240 AD, which is compared to the eruption of Krakatau in 1883. The breakout, with a VEI strength of six, began with smaller phreatomagmatic explosions . This was followed by plinian eruptions in which an estimated 30 to 36 kilometers high eruption column rise and about 15 cubic kilometers Tephra were promoted. At the same time, pyroclastic currents moved up to 20 kilometers from the crater; their deposits are estimated at 3 to 4 km³. In the second half of the eruption, the 4 to 6.5 kilometers large Caldera V formed with a volume of 6.5 to 7 km³. The ashes of the eruption were mainly distributed to the north and can still be detected 1000 kilometers away. In Kamchatka, the eruption had considerable ecological consequences: the vegetation was damaged on an area of ​​12,000 km²; at least 400 km² were completely devastated.

In contrast to the earlier caldera-forming eruptions of the Ksudatsch, which were followed by long periods of calm or only minor eruptions, further eruptions occurred around 100 years after the formation of Caldera V: Lava flows and moderate explosive eruptions built the Stübel volcano in the north of Caldera V. (вулкан Штюбеля, also Stubel and Shtyubel ' ). Named after the German natural scientist and volcanologist Moritz Alphons Stübel (1835–1904), the volcano was the starting point of two VEI-strength four eruptions around the years 1000 and 1750, in which pyroclastic flows or mud flows, so-called lahars , arose.

The only eruption of the Ksudach in historical times occurred in March 1907. In sparsely populated Kamchatka, the type and exact location of the eruptions remained unknown until an expedition visited the volcano in 1910. At the beginning of the eruption, two smaller, possibly phreatic explosions partially destroyed a lava dome that formed the top of the vortex. This cleared the way for the magma to reach the surface of the earth. The pressure relief triggered a Plinian eruption, which probably lasted several hours, in which a column of eruptions rose at least 22 kilometers high. Ash fall was registered 1000 kilometers away. After a short period of rest, a predominantly horizontal explosion occurred, which was probably triggered by the entry of water to the volcano's delivery system. The explosion destroyed the north-northeast portion of the vortex, causing water from an existing crater lake to come into contact with the magma. This triggered a series of hydromagmatic explosions , forming pyroclastic surges up to 15 kilometers in length . When VEI strength five erupted, around 2.4 km³ of tephra were extracted.

Basaltandesite and rhyodacite were mined during the Ksudach eruptions in the Holocene . The deposited tephra contains mafic and rockic pumice in many units , suggesting an intense mixture of rock melts during the eruptions.

present

Lake in the caldera of the Kudach

The highest point of Ksudach at 1079 meters is on the southern edge of Caldera I. Two lakes with a water level of 415 meters above sea level have formed in the caldera, which is bordered by steep walls, the Klyuchevoe Lake (oзеро Ключевое) in the south and the Stübel Lake (oзеро Штюбеля) in the north. A bay of the Stübel Lake fills the horseshoe-shaped crater of the Stübel volcano, which is open to the north-northeast; the lake should reach a depth of 300 meters in the crater area. The Stübel, classified partly as a tuff cone and partly as a cinder cone , reaches a height of 630 meters above sea level; in the 1907 eruption, the top 100 to 200 meters of the cone were destroyed. There are several thermal springs on the shore of Klyuchevoye Lake ; Gases rise in the area of ​​the Stübel crater.

Even in the present the area around the Ksudatsch is hardly developed. Helicopter flights to the caldera are offered for tourists. In addition, the Ksudatsch can be reached in multi-day hikes from Lake Kuril (50 kilometers southwest) and from the Mutnowski and Gorely volcanoes (around 90 kilometers north-northeast). The Kamchatka Volcanic Eruption Response Team (KVERT), an institution of the Russian Academy of Sciences , is responsible for monitoring the volcano . Ashfall in Petropavlovsk-Kamchatsky and in the Osernowski settlement 80 kilometers to the southwest are counted among the possible dangers that could arise from an eruption of the Ksudach . Lahars could also form, especially in the valley of the River Tjoplaja (Tёплая), which drains the caldera to the north.

literature

Web links

Commons : Ksudatsch  - collection of pictures, videos and audio files

Individual evidence

  1. ^ Macías, Products of the 1907 Eruption, p. 969.
  2. ↑ Volynetsa, Holocene Eruptive History, p. 25.
  3. ↑ Volynetsa, Holocene Eruptive History, pp. 25-29.
  4. ↑ Volynetsa, Holocene Eruptive History, p. 29;
    Benjamin J. Andrews, James E. Gardner, Steve Tait, Vera Ponomareva, Ivan V. Melekestsev: Dynamics of the 1800 14 C yr BP Caldera-forming Eruption of Ksudach Volcano, Kamchatka, Russia (pdf, 1.6 MB). In: J. Eichelberger, E. Gordeev, P. Izbekov, M. Kasahara, and J. Lees (Eds.): Volcanism and Subduction: The Kamchatka Region. (Geophysical Monograph Series, Volume 172), American Geophysical Union, Washington 2007, ISBN 978-0-87590-436-8 , pp. 325–342, here p. 336.
  5. ↑ Braitseva, Caldera-forming Eruption, p. 63.
  6. ^ Macías, Products of the 1907 Eruption, p. 970.
  7. ^ Ksudatsch near volcanoes of Kamchatka (Russian, accessed April 8, 2013).
  8. ↑ Ksudach - Eruptive History at the Global Volcanism Program (accessed April 4, 2013).
  9. ↑ Macías, Products of the 1907 Eruption, pp. 984 f.
  10. ↑ Ksudatsch at Holocene Kamchatka Volcanoes (English, accessed April 8, 2013).
  11. ↑ Macías, Products of the 1907 Eruption, pp. 969, 971.
  12. ↑ AG Nikolayeva, A. Yu. Bychkov: Content of Microelements in Hydrothermal and Lake Waters of Ksudach Volcano Caldera (South Kamchatka), p. 303 (English, pdf, 265 kB).
  13. ↑ Andreas von Heßberg: Discover Kamchatka. To the bears and volcanoes in northeast Siberia. Trescher, Berlin 2006, ISBN 3-89794-084-1 , p. 181.
  14. ↑ Ksudach volcano at KVERT - Kamchatka Volcanic Eruption Response Team (English, accessed April 4, 2013).