Report on Llaima (Chile) — 20 February-26 February 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 February-26 February 2008
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2008. Report on Llaima (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 20 February-26 February 2008. Smithsonian Institution and US Geological Survey.
38.692°S, 71.729°W; summit elev. 3125 m
All times are local (unless otherwise noted)
SERNAGEOMIN reported that weak steam plumes were observed from Llaima's main crater on 20 February. The 'a'a lava flow that traveled 2.5 km during 2-13 February varied in width between 30-40 m and was 10 m thick. On 21 February small ash plumes rose from the E and SE flanks. Pyroclastic flows descended the E flank and possibly down the W flank. Sulfur dioxide plumes that rose from two craters within the main crater were visible during an overflight. On 22 February, a seismic signal pattern similar to that observed during a previous pyroclastic flow was noted. Ash-and-gas plumes rose from the E flank. On 23 February, an ash-and-gas plume rose from the SE 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.