Report on Llaima (Chile) — 2 December-8 December 2009
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 2 December-8 December 2009
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2009. Report on Llaima (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 2 December-8 December 2009. Smithsonian Institution and US Geological Survey.
38.692°S, 71.729°W; summit elev. 3125 m
All times are local (unless otherwise noted)
Cameras operated by OVDAS-SERNAGEOMIN showed steam-and-gas plumes rising from Llaima's main crater and E flank during 14 November-1 December. Although seismicity generally decreased, a new type of long-period, low-frequency earthquake was detected. An overflight on 4 December revealed fumarolic activity and some sulfur dioxide emissions coming mainly from fissures on the N crater wall and outer E and W flanks. The Alert Level was raised to Yellow, Level 3. Activity last noted in the Weekly Volcanic Activity Report from 9-16 June was described as occasional steam emissions with minor amounts of ash rising from the E flank.
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.