Report on Llaima (Chile) — 16 April-22 April 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 April-22 April 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Llaima (Chile). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 16 April-22 April 2003. Smithsonian Institution and US Geological Survey.
38.692°S, 71.729°W; summit elev. 3125 m
All times are local (unless otherwise noted)
Llaima remained at Yellow alert at least through 16 April and eruptions began to contain significant tephra. Seismicity was almost 5-fold above background. Volcanologists expressed concern that the volcano=s glacial ice-cover could undergo local melting, which might lead to large and sudden outbursts of water (glacier bursts) down local drainages.
Geologic Background. Llaima, one of Chile's largest and most active volcanoes, contains two main historically active craters, one at the summit and the other, Pichillaima, to the SE. The massive, dominantly basaltic-to-andesitic, stratovolcano has a volume of 400 km3. A Holocene edifice built primarily of accumulated lava flows was constructed over an 8-km-wide caldera that formed about 13,200 years ago, following the eruption of the 24 km3 Curacautín Ignimbrite. More than 40 scoria cones dot the volcano's flanks. Following the end of an explosive stage about 7200 years ago, construction of the present edifice began, characterized by Strombolian, Hawaiian, and infrequent subplinian eruptions. Frequent moderate explosive eruptions with occasional lava flows have been recorded since the 17th century.