(Azerbaijani for “blue lake”), a lake on the northern slope of the Murovdag (Mrovdag) mountain range in the Azerbaijan SSR; one of the most beautiful mountain lakes in the USSR. Area, 0.78 sq km; average depth, 30 m; maximum depth, about 100 m. Located at an elevation of 1,566 m. The lake was formed as the result of a landslide and consequent damming of the Agsu River during an earthquake.