Lake Kussharo

About Lake Kussharo

A lake in the Kussharo caldera, formed by an eruption about 40,000 years ago; the Ministry of the Environment calls it Japan's largest caldera lake. Nakajima Island in the lake and Mt. Atosanupuri are volcanoes that grew after the caldera formed. When the lake freezes over in winter, the ice cracks and pushes up into ridges called omiwatari, up to 10 km long. Hot springs welling up from the lake bed keep part of it ice-free, and whooper swans arrive in late autumn. In the 1991 survey its water was acidic (acidotrophic).

Sources: Japan Meteorological Agency, Caldera volcanoes (National Catalogue of the Active Volcanoes in Japan), Ministry of the Environment, Akan-Mashu National Park: Highlights, Environment Agency of Japan, Lake Survey Report (1993) (sources in Japanese)

Lake data

Area

79.54 km²#2 in Hokkaido

Maximum depth

117.5 m#5 in Hokkaido

Average depth

28.4 m

Surface elevation

121 m

Transparency

6 m#11 in Hokkaidoas of the 1991 survey

Origin

Caldera lake

Lake type

Acidotrophic

Fresh or brackish

Freshwater

Freezing

Freezes in winter

Unmodified lake

No

Natural park

Akan-Mashu National Park

Lake number

0440number in the national lake survey

Sources: Geospatial Information Authority of Japan, Area Statistics of Prefectures and Municipalities 2026 (as of July 1), Geospatial Information Authority of Japan, Lake Survey (surveyed 1970-1971), Environment Agency of Japan, 4th National Survey on the Natural Environment: Lake Survey Report (1993). Area and depth use newer figures from the Geospatial Information Authority of Japan where available. Origin, lake type, transparency, freezing and unmodified status are as of the 1991 survey.

Themes that include Lake Kussharo

• Caldera lakes
• Acidotrophic lakes
• Freshwater lakes