Licancabur is a -high symmetrical cone. The cone, rising above the surrounding terrain, has a base diameter of and a total volume of . The top of the mountain is a -wide crater, and its slopes have an approximately 30° gradient. The volcano has erupted blocky lava flows, with thicknesses ranging from ; younger lava flows are thinner. Young lava flows on the western sides of the volcano are long; older flows extend . Some old lava flows reach Laguna Verde, and -long pyroclastic flow deposits have been found. The volcano's eastern and western flanks look different, since it formed on a basement which dips towards the Salar de Atacama. West of Licancabur are deposits stemming from debris avalanche activity, including blocks wide. The border between Bolivia and Chile, defined by the Treaty of Peace and Friendship (1904), crosses the volcano.