I will post the photos and location as a preservation of the site.
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The Origin of Zao Volcano (Summary)
About 35,000 years ago – Activity in the Horseback Caldera (basaltic andesite to andesitic magma activity)
13-40,000 years ago – Formation of Kumanodake volcano body (activity of andesite to basaltic andesite magma)
Approx. 500,000-200,000 years ago Formation of successive mountain bodies from Torikabuto-Yokogura-Yokogura-Yokogumano-Nakamaru-Yokogura-Yokogumano-Karitadake (andesitic magma-dominated activity)
About 1 million years ago Formation of the donkey’s ear volcanic zone (basaltic magma activity)
Ogama is a new crater formed by eruptions since prehistoric times
Okama is a volcanic lake
Okama, the symbol of the Zao Volcano, is a crater lake formed in the western part of Mt. The lake is also known as “Goshikinuma” because of the changing colors of its surface. The lake is approximately 300 m in length and has a maximum depth of 20 to 30 m. It is highly acidic and contains only a few diatoms.
Okama formed around 1200 AD.
The first eruption of Okama occurred around 1200 A.D. (beginning of the Kamakura period) and has been repeated many times since. The previous crater of Okama was located slightly to the east.
Goshikidake’s eruptions were explosive
Repeated explosive eruptions caused volcanic material to accumulate around the crater and the Goshikidake body to grow.
Photograph
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