Report on Villarrica (Chile) — 25 July-31 July 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 July-31 July 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Villarrica (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 25 July-31 July 2018. Smithsonian Institution and US Geological Survey.
39.42°S, 71.93°W; summit elev. 2847 m
All times are local (unless otherwise noted)
POVI reported that on 24 July the vent in Villarrica’s summit crater was about 10-15 m in diameter and 90-100 m below the crater rim. Minor explosions and weak fumarolic emissions were noted. On 29 July a break in the cloud cover revealed more significant incandescence emanating from the summit than in the previous few days, and the largest thermal anomaly since August 2015 was identified in satellite images on 30 July. Ash and lapilli deposits on the E edge of the crater was also visible on 30 July.
Geologic Background. Glacier-clad Villarrica, one of Chile's most active volcanoes, rises above the lake and town of the same name. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain. A 6-km-wide caldera formed during the late Pleistocene. A 2-km-wide caldera that formed about 3500 years ago is located at the base of the presently active, dominantly basaltic to basaltic-andesitic cone at the NW margin of the Pleistocene caldera. More than 30 scoria cones and fissure vents dot the flanks. Plinian eruptions and pyroclastic flows that have extended up to 20 km from the volcano were produced during the Holocene. Lava flows up to 18 km long have issued from summit and flank vents. Historical eruptions, documented since 1558, have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Glaciers cover 40 km2 of the volcano, and lahars have damaged towns on its flanks.