General information about Usoy Dam and Sarez Lake

General information about Usoy Dam and Sarez Lake has been presented. At the night from 18 to 19 on February, 1911 from the Southern slope of Muskol crest to valley of Murgab River a huge landslide has fallen. The reason for the displacement of rock massive was en earthquake with intensity of 9-10 force that has been registered many kilometers away, at Pulkovo observatory at the suburbs of Leningrad. The huge rock massifs and blocks buried the Usoy village with all inhabitants. As a result of this earthquake were partially destroyed a lot of villages. Half of the population of these mountain villages died. Landslide was moving with the speed up to 25 m/s, and has displaced boulder and shingle adjournments from bottom and boards of the Murgab river valley to the opposite slope. Landslide was accompanied by boulder and rock flows, up and down the valley of Murgab river. Length of the Usoy landslide from the beginning of the mud channel of Usoydara to the end of left contiguity is 5 km. Width from the head to tail waters is 5 km. Total area of the dam including underwater part is 12 km², maximum length is 650 m. With average height of 180 m volume of the landslide is 2.2 km³. Excess of the dam crest about lake level is not equal and at right contiguity makes 50 m and 230 m at the left one. The waters of the Murgab river started accumulate in front of formed dam and flooded one of the largest villages - Sarez. Filtration through Usoy dam started at April 1914.