Report on Villarrica (Chile) — September 1984
Scientific Event Alert Network Bulletin, vol. 9, no. 9 (September 1984)
Managing Editor: Lindsay McClelland.
Villarrica (Chile) Brief ash eruption; increased seismicity
Please cite this report as:
Global Volcanism Program, 1984. Report on Villarrica (Chile) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 9:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198409-357120.
39.42°S, 71.93°W; summit elev. 2847 m
All times are local (unless otherwise noted)
"A brief eruption from Villarrica's central crater was reported during the afternoon of 11 August. After three strong explosions and underground rumbling, a dark ash column was seen rising more than 200 m above the summit. Winds blew the ash over the snow-covered SE flank. Seismometers operated by the Universidad de la Frontera at Temuco (100 km NW of the volcano) recorded an increase in seismicity during the event."
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: H. Moreno R., Univ. de Chile, Santiago.