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Snow-covered Villarrica, one of Chile's most active volcanoes, rises above the lake and town of the same name. The volcano is also known as Rucapillan, a Mapuche word meaning "House of the Pillan". It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain along the Gastre Fault. Villarrica The volcano, along with Quetrupillan and the Chilean portion of Lanin, are protected within Villarrica National Park. Ascents of the volcano are popular with several guided ascents reaching the top during summer. On the volcano's lower slopes a ski resort has been working since 19XX.
Villarrica, with is lava of basaltic-andesitic composition is one of only four 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 atributted to the existence of an old fracture in the crust, the NWW-trending sinistral Gastre Fault Zone, the other volcanoesin the chain Quetrupillan and Lanin are far less active. This alignment is unusual as it crosses the N-S running Liquine-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 Villarricas otherwise quite effusive lava more viscous higherning its explosive potential. Two large ignimbrite layers are visible around the volcano; the Lican Ignimbrite and later the Pucon Ignimbrite.
The upper part of Villarrica is permanently covered by snow and has some 40 km2 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 Villarrca lost 25% of its glaciated surface. during the same period glaciers shrunk at an average rate of -0.4 km2 each year.Rivera, A., Acuna, C. and Casassa, G. Glacier variations in central Chile (32S-41S). Chapter in Glacier science.
Guided hikes to the crater are sometimes offered from the town of Pucon, but may be suspended in periods of seismic or increased volcanic activity. Helicopter sightseeing services offer flights over the crater as well. In the winter (July-September) skiing is practised on the northern slopes of Villarrica.
Villarrica is one of Chile's most active volcanoes and have had recorded eruption even since the time of the conquest of Chile and the founding of the city of Villarrica at its foothills in 1552. As in the case of other volcanoes in southern Chile eruptive record uncertainties exists in the first half of the 17th century due to the surrender or abandonment of Spanish settlements during the destruction of the Seven Cities. The earliest registered eruption was recorded in 1558 and there has since then been at least 65 eruptions with assumed Volcanic Explosivity Indexes of magnitude 1 or 2.
The two last weeks of February in 1964 the volcano showed signs of unrest such as small but still violent lava effusions followed by temblors. On March 1 at 2.45 am the volcano begun a strombolian eruption. Dwellers at Conaripe, a wood-logger town, woke up in the night and fled to the surroundings hills while it was raining after hearing strong noises and temblors. As the volcano was capped by an early autumn snowfall to its foothills the melting for snow and ice from Pichillancahue-Turbio Glacier produced together with the heavy rainfalls several lahars. Conaripe then located on the northwestern shores of Calafquen Lake had about half of the buildings destroyed and was later reconstructed further east.
On October 29, 1971, at 4 o'clock on the morning, several explosions were heard from the crater according to skiers and staff working at the Villarrica ski resort on the slope of the volcano. The same day a small column of white smoke was seen at the top of the volcano and later the same day the white column alternated with black smoke. One month later on December 29, quarter to midnight, Villarrica begun a new eruptive cycle. Pyroclasts were ejected and the snow surrounding the crater and on some parts of the slopes melted due to the heat. This was followed by a brief halt in activity followed by the opening of a new vent in the northeast flank through which lava went out. The lava flows melted considerable amounts of snow, causing several lahars that went down through the troughs and valleys of the volcanic edifice. The lahars affected the localities of Pichaye, El Turbio, Collentane, Minetue, Molco, Voipir and Curarrehue all of them in Trancura River's basin. In the larger settlements of Villarrica and Pucon toxic sulphurous gases from the volcano turned the air unbreathable for moments. At least 15 people are reported to have died because of the eruption.
List of volcanoes in Chile
Satellite photo of Villarrica Volcano
Villarrica Volcano info on SummitPost.com
top of the volcano ...
Villarrica Volcano Visual Observation Project
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article Villarrica (volcano)