Antuco volcano in central Chile rises majestically above the SW shore of Laguna de la Laja. Antuco is one of Chile's more active volcanoes. Mild explosive eruptions were recorded in the 18th and 19th centuries from both summit and flank vents, and historical lava flows have traveled into the Río Laja drainage.

The formation of Antuco volcano followed the older stratovolcanoes of the basaltic-to-andesitic Sierra Veluda and Cerro Condor.

Antuco volcano itself of two units, separated by a caldera collapse, and are referred to as Antuco I and Antuco II, and a flank cone. Antuco I grew until about 10,000 years ago to form a 10 km diameter stratovolcano. Its end was marked by a large sector collapse, producing a large debris avalanche which traveled down the Río Laja to the west and left a large 5-km-wide horseshoe-shaped caldera breached to the west.

Afterwards, new activity built a new cone, now rising over 1000 m, inside the caldera, Antuco II, and a parasitic cone on the NE flank of the Antuco I.