Batur caldera is situated at 115' 19' to 115' 26' and 80' 11' to 80' 18', on the island of Bali, Indonesia. It lies on the Sunda-Banda volcanic island arc (Hamilton, 1978), and includes calc-alcaline volcanoes (Whitford and Nichols, 1973). It consist of two calderas, the inner is 7 km diameter and the outer is 11 to 15 km diameter.