Report on Villarrica (Chile) — 4 February-10 February 2015
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 February-10 February 2015
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2015. Report on Villarrica (Chile). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 4 February-10 February 2015. Smithsonian Institution and US Geological Survey.
39.42°S, 71.93°W; summit elev. 2847 m
All times are local (unless otherwise noted)
Projecto Observación Visual Volcán Villarrica (POVI) reported that at night during 4-5 February faint incandescence was detected with a near-infrared camera. On 5 February Strombolian explosions ejected tephra several hundred meters high. On 6 February tephra was ejected about 65 m above the crater rim and two consecutive ash emissions were observed. OVDAS-SERNAGEOMIN reported that the Alert Level for Villarrica was raised to Yellow (the second lowest level on a four-color scale) due to the increased seismicity, indicating a fluctuating lava lake and small explosions. Scientists noted a rise in the lava-lake level during an overflight. POVI reported that on the morning of 7 February bombs were ejected from the crater, some almost 5 m in diameter. Later that day the intensity of the explosions decreased and crater incandescence became irregular.
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.