Asama

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Asama
Asama in 2005

Asama in 2005

height 2568  m
location Honshū , Japan
Coordinates 36 ° 24 ′ 0 ″  N , 138 ° 31 ′ 0 ″  E Coordinates: 36 ° 24 ′ 0 ″  N , 138 ° 31 ′ 0 ″  E
Asama (Gunma Prefecture)
Asama
Type complex volcano
Last eruption 2019

The Asama ( Japanese 浅 間 山 , -yama ) is a complex volcano on the Japanese island of Honshū . It is located around 150 kilometers northwest of Tokyo on the border of the Gunma and Nagano prefectures . The Asama is the most active volcano on the island of Honshu.

construction

The Asama is located a little east of the Kurofu , a volcano made of andesite that was destroyed by a landslide around 20,000 years ago. Subsequently, a shield volcano from Dacite was created ; it was the starting point of pyroclastic currents in particular 11,000 to 14,000 years ago . At the same time, the Ko-Asama lava dome was built , located around three kilometers east of today's summit. All eruptions in historical times originated from the maekake , which is probably a few thousand years old. On top of the maekake is the coma , a pyroclastic cone that is the summit of the volcano with a height of 2568 meters.

outbreaks

Numerous eruptions are known from historical times ; there were particularly strong eruptions in 1108 and 1783. The eruption of 1108 is associated with climatic changes in England in 1110 and an unusual darkening of the moon in May of the same year, which was described in the Peterborough Chronicle .

“On the fifth night in the month of May appeared the moon shining bright in the evening, and afterwards by little and little it's light diminished, so that, as soon as night came, it was so completely extinguished withal, that neither light, nor orb, nor anything at all of it was seen. "

“On the fifth night of May, the moon appeared brightly shining in the evening, and after that the light gradually diminished so that as soon as night came it was so completely extinguished that neither light nor celestial bodies nor anything else of it Was seen."

- Peterborough Chronicle

The unusual atmospheric-optical phenomenon is associated with volcanic aerosols of the Asama at high altitudes.

The eruption between May and August 1783 resulted in Vulcanian and Plinian eruptions ; pumice stone was promoted for the latter . Lava also flowed out and pyroclastic currents formed. Around 1,500 people died in the eruption, partly from the pyroclastic currents and partly from floods that resulted from the eruption. The amount of dust and ash emitted reduced the amount of sunlight, making the weather cold and rainy. Between 1783 and 1787 there was a famine in northern Japan, in which an estimated 300,000 people died. The Asama eruption is cited as one of several causes of the famine. The Asama eruption had only a minor impact on the exceptionally cold winter of 1783/84 compared to the Laki craters in Iceland, which also erupted in 1783 .

The last eruptions of the Asama were in 2004, 2008, 2009 and 2019. Between September and November 2004 there were several explosive eruptions in which ashes were ejected. A new lava dome temporarily formed in the crater.

Since 1933, the University of Tokyo has operated a volcano observatory on Asama, which is located on the eastern slope at an altitude of around 1,400 meters. The observatory was the first of its kind in Japan and contributed significantly to the development of volcanology in Japan. In particular, earthquakes that often precede volcanic eruptions have been researched.

Web links

Commons : Asama  - collection of images, videos and audio files

Individual evidence

  1. ↑ Asama in the Global Volcanism Program of the Smithsonian Institution (English)
  2. ↑ a b Sébastien Guillet, Christophe Corona, Francis Ludlow, Clive Oppenheimer, Markus Stoffel: Climatic and societal impacts of a “forgotten” cluster of volcanic eruptions in 1108-1110 CE. In: Scientific Reports. 10, 6715, 2020, doi: 10.1038 / s41598-020-63339-3 .
  3. ↑ Maya Yasui, Takehiro Koyaguchi: Sequence and eruptive style of the 1783 eruption of Asama Volcano, central Japan: a case study of an andesitic explosive eruption generating fountain-fed lava flow, pumice fall, scoria flow and forming a cone. In: Bulletin of Volcanology , 66 (2004), pp. 243-262 doi : 10.1007 / s00445-003-0308-8
  4. ^ Asama 1783 in The Significant Volcanic Eruption Database of the NOAA (accessed March 8, 2013).
  5. ^ GA Zielinski, RJ Fiacco, Paul Andrew Mayewski, LD Meeker, S. Whitlow, MS Twickler, MS Germani, K. Endo, M. Yasui: Climatic Impact of the AD 1783 Asama (Japan) Eruption was Minimal: Evidence from the GISP2 Ice Core. (1994). Earth Science Faculty Scholarship, Paper 191 (English, pdf, 492 kB).
  6. ↑ Mount Asama volcano erupts | NHK WORLD-JAPAN News. Retrieved August 7, 2019 .
  7. ↑ Monthly reports 08 / 2004–02 / 2005 in the Global Volcanism Program. (English, accessed March 10, 2013).
  8. ↑ Asama Volcano Observatory (AVO) at www.eri.u-tokyo.ac.jp (English, accessed on March 10, 2013).
  9. ↑ Vyacheslav M. Zobin: Introduction to volcanic seismology. Elsevier, Amsterdam 2003, ISBN 0-444-51340-X , p. 13;
    John P. Lockwood, Richard W. Hazlett: Volcanoes: Global perspectives. Wiley-Blackwell, Chichester 2010, ISBN 978-1-4051-6250-0 , p. 38.