Report on Villarrica (Chile) — 12 May-18 May 2010
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 12 May-18 May 2010
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2010. Report on Villarrica (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 12 May-18 May 2010. Smithsonian Institution and US Geological Survey.
39.42°S, 71.93°W; summit elev. 2847 m
All times are local (unless otherwise noted)
On 12 May, OVDAS-SERNAGEOMIN reported that a slight increase in activity from Villarrica during April led to a change in the Alert Level from Green Level 1 to Green Level 2. April's activity was characterized by increased seismicity, a rise in the lava lake level, more vigorous fumarolic activity, and more frequent incandescence at night. According to the Projecto Observación Visual Volcán Villarrica (POVI), the spattering lava lake was about 100 m below the crater rim on 10 May.
Geologic Background. Glacier-clad Villarrica, one of Chile's most active volcanoes, rises above the lake and town of the same name. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain. A 6-km-wide caldera formed during the late Pleistocene. A 2-km-wide caldera that formed about 3500 years ago is located at the base of the presently active, dominantly basaltic to basaltic-andesitic cone at the NW margin of the Pleistocene caldera. More than 30 scoria cones and fissure vents dot the flanks. Plinian eruptions and pyroclastic flows that have extended up to 20 km from the volcano were produced during the Holocene. Lava flows up to 18 km long have issued from summit and flank vents. Historical eruptions, documented since 1558, have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Glaciers cover 40 km2 of the volcano, and lahars have damaged towns on its flanks.