Report on Llaima (Chile) — June 1998
Bulletin of the Global Volcanism Network, vol. 23, no. 6 (June 1998)
Managing Editor: Richard Wunderman.
Llaima (Chile) Park ranger reports puffing steam plumes and fine-ash ejecta
Please cite this report as:
Global Volcanism Program, 1998. Report on Llaima (Chile) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 23:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199806-357110.
38.692°S, 71.729°W; summit elev. 3125 m
All times are local (unless otherwise noted)
On [about 3-4] April 1998, Miguel Torres, a park ranger in Llaima's N sector (Conguillío) saw steam and fine ash ejected. Falling ash later mantled solar panels. [Additional activity was observed during 22-23 April by J.A. Naranjo.]
A series of events were noted on 22 April, a clear sunny day but some cloudiness on the mountain's slopes. At 1015 from an undisclosed distance to the NNW, [Naranjo] observed puffs of white color emitted at 2-minutes intervals from the N crater. This became a dense grayish white plume that ascended and headed ENE. During this emission, visible fumaroles elsewhere continued unchanged.
At 1040 [Naranjo] noted a decrease in activity, or possibly a shift in atmospheric conditions, that decreased the amount of visible condensation. He still saw puffs of condensing gases, but at much lower intensities than earlier. At 1045, from the Colorado river area he noted a further decrease in activity, with gas puffs escaping at intervals of over 2.5 minutes. At 1054 the plume dissipated and blew SE.
The next day, there were fewer clouds on the slopes. At 0925, [Naranjo] saw Llaima issue a blue-gray plume that advanced ENE. The amount of visible condensation was less than the previous day, however, presumably because of lower relative humidity in the ambient air surrounding the crater and summit. At 1245 [Naranjo] was watching from the E (the sector containing Lake Arcoiris) when a clear increase in steam discharge from the principal crater became apparent; puffs of steam ascended at intervals of 30-35 seconds. The puffs emerged from different parts of the main crater, perhaps due to air turbulence. At this time, minor fumarolic activity also prevailed in the S crater (Pichillaima); this crater regularly gives off sparse plumes even though it has not erupted since 1957. At 1321 [Naranjo] watched clouds form and spread out above the volcano.
Despite these visual observations, Gustavo Fuentealba reported in late July 1998 that Llaima's recent seismic activity had appeared normal.
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.
Information Contacts: Jose Antonio Naranjo, Programa Riesgo Volcánico, Servicio Nacional de Geología e Minería (SERNAGEOMIN), Av. Santa María 0104, Casilla 10465, Santiago, Chile; Gustavo Fuentealba C., Observatorio Volcanológico de Los Andes del Sur (OVDAS), Manantial 1710-Carmino del Alba, Temuco, Chile.