Cordón del Azufre is a small, inactive complex volcano located in the Central Andes, at the border of Argentina and Chile. Geology and geomorphology The volcano lies at the border between Argentina and Chile and contains a series of craters and lava flows covering a surface area of . A western component with four craters aligned in a north–south direction on a ridge forms the oldest part. Numerous monogenetic volcanoes and stratovolcanoes developed on it and buried most of its central crater under lava flows. A pile of lava flows covers an area of on the eastern side. The eastern component is formed by lava flows and craters in Argentina, and the youngest part la Moyra volcano in the western component generated a lava flow that advanced westwards. Weakly porphyritic andesite and dacite form the rocks of the volcano. Lava flows of the eastern component have been dated to be 600,000 years old. No activity, including fumarolic activity, has been recorded at Cordón del Azufre, but the appearance (dark and pristine) and radiometric age (0.3 ± 0.3 mya K-Ar on the most recent flow) of the lava flows suggest a recent age. Pyroclastic deposits are linked to the youngest cone may date to a historical eruption. Renewed activity would likely consist of lava flows and pyroclastic deposits and, in light of the total lack of important roads and habitation, potential future eruptions are no threat. Geographic context It is located east of the Chile Trench within the Puna where the volcanic arc intersects a probably deep-seated structural area named the Archibarca corridor. Since the Eocene, underlying convergence and subduction of the Nazca plate at a speed of result in the volcanic activity of the Central Volcanic Zone (CVZ), the activity of fault zones and active deformation south of 23° S. Several large calderas lie in the CVZ, some of which (Galan, La Pacana) have erupted volumes of over . The area is uninhabited and remote. Ground deformation Observations of this volcano and neighbouring Lastarria indicate that they are part of an actively deforming system, named by Pritchard and Simons (2002) the Lazufre system with an axis length of . The modelled centre of deformation is closer to Azufre than Lastarria. Sometimes Cerro Bayo Gorbea is also associated to this complex. This inflation started in the late 1990s and is probably due to the accumulation of volcanic fluids (hydrothermal or magmatic)