Report on Villarrica (Chile) — 1 April-7 April 2015
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 1 April-7 April 2015
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2015. Report on Villarrica (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 1 April-7 April 2015. Smithsonian Institution and US Geological Survey.
39.42°S, 71.93°W; summit elev. 2847 m
All times are local (unless otherwise noted)
OVDAS-SERNAGEOMIN reported that during 31 March-4 April small Strombolian explosions at Villarrica continued, and seismicity slightly and steadily increased. During 4-5 April pulsating emissions of water vapor and ash rose 700 m above the crater. Strombolian explosions sometimes ejected material outside the crater, onto the flanks, at distances no greater than 200 m. Pulsating gas-and-ash emissions continued at a lower level during 6-7 April. Nighttime incandescence from the crater was occasionally observed, and seismicity decreased. The Alert Level remained at Orange (the second highest level on a four-color scale) and the public was warned to stay outside of a 5-km radius around the crater and away from drainages.
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.