Crater lake

This page describes the geological feature. For the lake of the same name, see Crater Lake.

Crater Lake in Oregon: view from the rim.

A crater lake is a lake that forms in volcanic calderas or craters after the volcano has been inactive for some time. The best-known crater lake, which bears the same name as the geological feature, is Crater Lake in Oregon state's Mount Mazama. Some crater lakes are acidic, however, some lakes' water remains fresh. Some also have geothermal activity, especially if the volcano is merely dormant rather than extinct.

Crater Lake in Crater Lake National Park is isolated from rivers and streams, and therefore has no in or out flow, and hense, no pollution or chemicals. It is fed by melting snow. The extreme depth of Crater Lake (1949 feet), causes the sunlight to refract in the clear water in such a way as to generate the deepest blue color of any other lake.

Lakes can also fill craters formed by impact events. An example is the Bosumtwi crater in Ghana, Africa.

Visual

• Crater Lake Virtual Tour by San Fancisco Click

See also

• Maar

Notable Crater Lakes

• Crater Lake (Oregon, USA)
• Kapoho Crater (Hawaii, USA)
• Kelut (Indonesia)
• Lake Nyos (Cameroon)
• Mount Pinatubo (Philippines)
• Soufrière (St. Vincent)