Cerro del Azufre ("sulphur peak") volcano is a large andesitic stratovolcano in northern Chile 20 km from the border with Bolivia. It is the largest and youngest volcanic center of a 50-km-long, NW-SE-trending chain of volcanoes south of Salar de Ascotán. The volcano has 2 summits, the northern peak forming the summit and the lower southern peak (5700 m) belonging to an earlier stratovolcano, which extends towards the extinct Cerro Aguilucho volcano. It is uncertain whether the volcano has erupted in the past 10,000 years. There are a number of fresh-looking lava domes and craters, but in this region erosion and weathering are so inefficient that such craters can look young, but are actually hundreds of thousands of years old. Note: there is a volcano with a similar name - "Cordon del Azufre" in northern Chile.

A large group of lava flows were erupted from the northern cone and extend 7 km north from the volcano. The partly overly a debris-avalanche deposit, which continues under the Salar de Ascotán salt flat.

The most recent effusive activity occurred from dacitic lava domes located along a NW-SE line east of the summit ridge.

The Chanka (Pabellón) dacitic lava-dome complex occupies the lower western flank. It looks young, but is actually 1.5 million years old, because the process of erosion and weathering in the dry arid climate is very low.

2 possible Holocene dacitic lava domes were erupted along a NW-SE line east of the summit ridge and mark the most recent effusive activity of the Cerro del Azufre complex. As well, 2 youthful-looking craters on the main edifice could be of Holocene age.