Report on Villarrica (Chile) — August 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 8 (August 1991)
Managing Editor: Lindsay McClelland.
Villarrica (Chile) Weak explosions
Please cite this report as:
Global Volcanism Program, 1991. Report on Villarrica (Chile) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 16:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199108-357120.
39.42°S, 71.93°W; summit elev. 2847 m
All times are local (unless otherwise noted)
An increase in fumarolic activity and weak explosions were observed in the crater during August-September. On 26 August, water in a nearby river (Río Carmelito) was cloudy and the river level abnormally high. Four days later, on 30 August, small ash emissions and continuous explosions were observed from 1430 to 1500, followed by a strong explosion at 1506. A weak emission of gray ash and a white gas plume 1 km high were observed on 17 September. Seismicity was at normal levels for the volcano.
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.
Information Contacts: G. Fuentealba and P. Riffo, Univ de la Frontera.