Report on Villarrica (Chile) — 16 October-22 October 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 October-22 October 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Villarrica (Chile). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 16 October-22 October 2002. Smithsonian Institution and US Geological Survey.
39.42°S, 71.93°W; summit elev. 2847 m
All times are local (unless otherwise noted)
During visits to Villarrica's summit in September observers saw incandescence until the 28th. On the 28th deep sounds emanated from the volcano every 1-2 minutes and lapilli deposits were seen on the crater's edges. On 16 October incandescence was not visible and strong, deep noises were heard every 7-10 minutes.
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.