Volcanism in the region occurs because of the Southern Volcanic Zone and the Austral Volcanic Zone. These contain about 74 volcanoes with post-glacial activity; they include both monogenetic volcanoes, stratovolcanoes and volcanic complexes. Llaima and Villarrica are among the most active of these volcanoes. The Southern and Austral volcanic zones are separated by a gap without volcanic activity, close to the Chile Triple Junction.