Cryptodepression

When the bottom of the lake lies below mean sea level, it is said to occupy a cryptodepression, the depth of which is the depth below sea level of the deepest point of the basin.

The lake's elevation above sea level is 74.01 meters (242.8 feet) which makes its depth of cryptodepression to be 170 meters (558 feet).

The greater volume of the lake [Lake Susupe] occupies a cryptodepression (that portion which lies below sea level). Based upon a surface elevation of +2.5 ft determined on 20 December 1978 by Juan C. Tenorio and Associates' surveyors, the depth of the cryptodepression is -1.4m (4.7 ft) below sea level.

At present there are three major closed systems (Awash R. – Afar drainage, northern rift lakes, southern rift lakes), numerous crater lakes with seepage-in and -out, and two cryptodepressions with marine inputs.

The maximum depth of some lakes is below current sea level. Such lakes are called cryptodepressions. Well-known cases of tectonic lakes include Lake Baikal and the Caspian Sea. Some glacial lakes in Norway, Scotland and England are also cryptodepressions.