Planchón-Peteroa

The Río Teno debris avalanche, triggered by a sector collapse approximately 11,500 years ago, traveled 95 km from the summit to Chile's Central Valley — one of the longest volcanic landslide runout distances in the Andes.

Planchón-Peteroa straddles the Chile-Argentina border, making it one of the few volcanoes jointly monitored by two nations' geological agencies.

The complex comprises three distinct volcanic centers — Azufre, Planchón, and Peteroa — built over different geological periods from the Pleistocene to the Holocene.

Lava flows were emplaced during both the 1837 and 1937 eruptions, the only confirmed effusive events in the complex's historical record.

The 1762 eruption reached VEI 4, making it the largest explosive eruption in the complex's written history and comparable to major events at Villarrica and Llaima.

Peteroa's crater lake serves as a natural thermometer — changes in its temperature, color, and chemistry provide early warning of shifts in volcanic activity.

Volcán Azufre, the oldest center in the complex, produced lavas ranging from basaltic andesite to dacite, indicating a chemically diverse magmatic system.

The 1889–1894 eruption lasted approximately five years, the longest continuous eruptive episode documented at Planchón-Peteroa.

The complex's elongated north-south geometry spans approximately 10 km along the Andean crest.

Planchón-Peteroa erupted as recently as October 2025, confirming its status as one of Chile's most persistently active volcanic systems.

The name 'Peteroa' derives from the Mapudungun language of the indigenous Mapuche people.

Ash from the 2011 eruption drifted eastward across the Andes into Argentine Patagonia, affecting areas hundreds of kilometers from the summit.