Portal de Periódicos da CAPES

Lake Akanuma, a Siderotrophic Lake, at the Foot of Volcano Bandai, Hukusima Prefectre, Japan

1935; Project Euclid; Volume: 11; Issue: 10 Linguagem: Inglês

10.2183/pjab1912.11.426

1881-1140

Shinkichi YOSHIMURA,

Geochemistry and Elemental Analysis

Mt. Bandai (1,819 m) is a volcano in northeastern Honsyu and famous for its sudden violent explosion which occurred on July 15, 1888, when two-thirds of its peak, Mt.Kobandai, blew off.A mud-flow of the material that formed Kobandai, rushed down the valley of the river Nagase and dammed it, resulting in making there four lakes, Hibarako (10.27 sqkm, 31 m.deep), (Onogawako (1.41 sqkm.21.8 m), Sobarako (0.37 sqkm, 12.0 m), and Akimotoko (3.87 sqkm, 34.5 m).There are still remains today, as remnants, many small undrained depressions on the surface of the mud-flow, one hundred or more in total number ; they are called Gosikinuma, or five-coloured lakes, because of their water being tinged with emerald, bright blue, red or green.Akanuma, in one of these depressions, is a small narrow lake (2,300 sqkm) at a height of 795 m, without any outflow and surrounded on all sides by low cliffs of the old mud-flow now overgrown with pine trees.The writer visited this lake with Messrs K. Negoro and A. Yamamoto in August, 1935.Upon sounding at 8 points from a rubber boat, its maximum depth was measured to be 4.0 m ; the bottom was as a whole flat.The most striking feature of the lake was the extraordinary red dish green colour of its water, Akanuma in Japanese meaning red lake or pond.The water was turbid owing to ferric oxide in suspen sion ; the white disc is invisible at 1.2m.The following hydrographical observations were made in the after noon of 18th, under the cloudless sky (Table I).TABLE I. No. 10.1 Lake Akanurna, a Siderotrophic Lake, at the Foot of Volcano Bandai.