 Cerro Azul is part of the South Volcanic Zone , which runs through central and western Chile and extends south to Argentina . This range includes at least nine caldera complexes , more than 70 of Chile 's stratovolcanoes and volcanic fields that have been active in the Quaternary , and hundreds of minor eruptive centres . The South Volcanic Zone is the most volcanically active region in Chile , and produces around one eruption per year . Its largest historical eruption was at Quizapu Crater , located on the north side of Cerro Azul 's summit ( see below ) , and its most active volcanoes are Llaima and Villarrica . 
