Report on Lascar (Chile) — July 1996
Bulletin of the Global Volcanism Network, vol. 21, no. 7 (July 1996)
Managing Editor: Richard Wunderman.
Lascar (Chile) Quiet emission of vapor
Please cite this report as:
Global Volcanism Program, 1996. Report on Lascar (Chile) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 21:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199607-355100.
23.37°S, 67.73°W; summit elev. 5592 m
All times are local (unless otherwise noted)
In July 1996, activity was observed during a two-week period. Vapor quietly puffed several times per minute. The white to bluish color and smell of the vapor suggested that it consisted mainly of H2O and SO2. No rumbling was perceptible 300 m below the S rim of the crater.
Geologic Background. Láscar is the most active volcano of the northern Chilean Andes. The andesitic-to-dacitic stratovolcano contains six overlapping summit craters. Prominent lava flows descend its NW flanks. An older, higher stratovolcano 5 km E, Volcán Aguas Calientes, displays a well-developed summit crater and a probable Holocene lava flow near its summit (de Silva and Francis, 1991). Láscar consists of two major edifices; activity began at the eastern volcano and then shifted to the western cone. The largest eruption took place about 26,500 years ago, and following the eruption of the Tumbres scoria flow about 9000 years ago, activity shifted back to the eastern edifice, where three overlapping craters were formed. Frequent small-to-moderate explosive eruptions have been recorded since the mid-19th century, along with periodic larger eruptions that produced ashfall hundreds of kilometers away. The largest historical eruption took place in 1993, producing pyroclastic flows to 8.5 km NW of the summit and ashfall in Buenos Aires.
Information Contacts: J. Sesiano, Département de Minéralogie, Université de Genève, 13 rue des Maraîchers, 1121 Genève 4, Switzerland.