Villarrica is one of Chile's most active volcanoes, rising above the lake and town of the same name. The volcano is also known as Rucapillán, a Mapuche word meaning "House of the Pillán". It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain along the Gastre Fault. Villarrica, along with Quetrupillán and the Chilean portion of Lanín, are protected within Villarrica National Park. Ascents of the volcano are popular with several guided ascents reaching the top during summer.
Villarrica, with its lava of basaltic-andesitic composition, is one of only five volcanoes worldwide known to have an active lava lake within its crater. The volcano usually generates strombolian eruptions, with ejection of incandescent pyroclasts and lava flows. Melting of snow and glacier ice as well as rainfalls often cause massive lahars (mud and debris flows), such as during the eruptions of 1964 and 1971.
Geography and Geology :
Villarica's symmetrical edifice stands in the Chilean Central Valley as the westernmost of an alignment of three large stratovolcanoes. The alignment is attributed to the existence of an old fracture in the crust, the North West-West trending sinistral Gastre Fault Zone, the other volcanoes in the chain Quetrupillán and Lanín are far less active. This alignment is unusual as it crosses the N-S running Liquiñe-Ofqui Fault, around which most currently active volcanoes are aligned. Currently the volcano covers up an area of 400 km2 and has a volume 250 km3 according to estimates.
About 25 scoria cones dot Villarica's flanks. It also has volcanic caves. The constant degassing at the lava lake turns Villarrica's otherwise quite effusive lava more viscous, heightening its explosive potential. Two large ignimbrite layers are visible around the volcano; the Licán Ignimbrite and later the Pucón Ignimbrite.
The upper part of Villarrica is permanently covered by snow and has some 40 km square of glaciers. The largest glacier of Villarrica is the Pichillancahue-Turbio Glacier situated on its southeastern flank, which has the most favorable environment for glacier formation. Ashfalls from the frequent eruptions of the volcano do sometimes enhance ablation due to increased absorption of solar radiation. Some ash coverings around Villarrica are thicker than 5 cm and insulates the glacier decreasing ablation instead of enhancing it. Between 1961 and 2003, Villarrica lost 25% of its glaciated surface. During the same period glaciers shrunk at an average rate of -0.4 km2 each year.
Villarrica is one of the World's most climbed stratovolcanoes. Guided hikes to the crater are offered from the town of Pucón by several enterprises, but may ascent might be suspended due to cloudiness and in periods of seismic or increased volcanic activity. Helicopter sightseeing services offer flights over the crater as well. In the winter (July–September) a ski resort operates on the northern slopes.
Elevation : 2,847 m (9,341 ft)
Type : Stratovolcano
Age of rock : < Upper Pleistocene
Last eruption : 2011