Lake Shikotsu

A typical caldera lake located in the west of Chitose City in southwest Hokkaido. It has a circumference of 40 km, an area of ​​77.3 square km, a water surface elevation of 248 m, and a maximum depth of 360.1 m, making it the second deepest lake in Japan, and it does not freeze over in winter. During the Würm glacial period about 30,000 years ago, there was a large amount of volcanic activity, and the resulting pumice flows reached the southern part of Sapporo City and the eastern part of the Umaoi Hills. The eruption of this welded tuff created a circular caldera, but later, Mt. Eniwa erupted in the north, and Mt. Fuppushi and Mt. Tarumae erupted at the symmetrical point, creating a cocoon-shaped lake shore. The Chitose River breaks through the caldera wall on the east side and flows out. Near the outlet, there is a narrow flat area where tourist hotels, souvenir shops, and a bus center are located. However, for the most part, the caldera wall is close to the water surface, forming steep cliffs, leaving a tranquil atmosphere. During the 1972 Sapporo Olympics, Mt. Eniwa on the north wall was used as the downhill course, with the lakeshore as the final point, but it was later removed. On the northwestern lakeshore, there are hot springs, Shikotsu Lake Ito and Marukoma Onsen, and on the eastern shore, Shikotsu Lake Onsen. Lake sightseeing boats connect the lakeside base, and the lakeside road and Lake Shikotsu National Highway are also used. Himemasu, which were introduced from Lake Akan, have been successfully cultivated, and tip fishing (the Ainu name for himemasu) in the summer has become a specialty.

[Narabe Osamu]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

北海道南西部、千歳市(ちとせし)西部にある標式的カルデラ湖。周囲40キロメートル、面積77.3平方キロメートル、水面標高248メートル、最深部360.1メートルで国内第二の深さをもち、冬も結氷しない。約3万年前のビュルム氷期に大火山活動があり、その軽石流は札幌市南部、馬追(うまおい)丘陵東部にまで及んでいる。この溶結凝灰岩の噴出により、円形のカルデラができたが、その後、北部に恵庭岳(えにわだけ)、対称地点に風不死岳(ふっぷしだけ)、樽前山(たるまえさん)が噴出し、繭型の湖岸となった。東側のカルデラ壁を破って千歳川が流出し、その出口付近に狭い平地があって、観光ホテル、土産物(みやげもの)店、バスセンターなどが立地するが、大部分はカルデラ壁が水面に迫って急崖(きゅうがい)をつくり、静寂な趣(おもむき)を残している。1972年（昭和47）の札幌オリンピックのとき、北壁の恵庭岳が滑降コースになり、湖岸を決勝点としたが、その後撤去された。北西側の湖岸に、支笏湖いとう、丸駒温泉(まるこまおんせん)、東岸に支笏湖温泉の各温泉が湧出(ゆうしゅつ)し、湖上遊覧船で湖畔の基地と結ぶほか、湖畔道路、支笏湖国道などが利用される。阿寒(あかん)湖から移入されたヒメマスの養殖が成功し、夏のチップ釣り（ヒメマスのアイヌ名）が名物になっている。

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