Report on Villarrica (Chile) — June 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 6 (June 1993)
Managing Editor: Edward Venzke.
Villarrica (Chile) High-frequency seismicity increases
Please cite this report as:
Global Volcanism Program, 1993. Report on Villarrica (Chile). In: Venzke, E (ed.), Bulletin of the Global Volcanism Network, 18:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199306-357120.
39.42°S, 71.93°W; summit elev. 2847 m
All times are local (unless otherwise noted)
The telemetered seismic station located 4 km NW of the main crater at 1,400 m elev recorded 11 high-frequency events (A-type) in June, compared to 3 in May, 1 in April, and 1 in March. Since March, ~ 25,000 tremor episodes have been recorded; ~ 6,000-7,000/month.
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, M. Murillo, M. Petit-Breuilh, and P. Peña, SAVO, Univ de la Frontera, Fundación Andes; J. Cayupi, SERNAGEOMIN.