It is situated in the south part of the peninsula on the fissure zone of the Mid-Atlantic Ridge and can be reached via a track. Its greatest depth is 97 m.
After the big earthquake in 2000, the lake began to diminish. 20% of its surface have since disappeared.
Not far from the lake, two areas with high temperature can be found: Seltún/Krýsuvík and another to the east of the lake
Kleifarvatn is draining at about one centimeter (one-third of an inch) a day, according to Clifton.
Describing herself as a "walking pencil," because her treks are all mapped by global positioning system (GPS) technology, she investigates open cracks, torn vegetation, rock falls, sinkholes, and other disturbances and tries to determine what caused them.
The earthquake thought to be responsible for the fissure at Lake Kleifarvatn occurred last year on June 17, about 80 kilometers (49 miles) east in the South Icelandic seismic zone.