POVI counted 21 Strombolian events that ejected incandescent material onto Villarrica’s upper SW flank from 2200 on 28 December to 0540 on 29 December. More than 100 Strombolian events ejected incandescent material onto the upper W and NW flanks during 30-31 December. Observatorio Argentino de Vigilancia Volcánica (OAVV) reported that an explosion at 2356 on 31 December ejected incandescent material onto the upper NW flank as far as 480 m from the crater rim, and an explosion at 0219 on 31 December ejected incandescent material onto the same flank as far as 150 m. Both explosions ejected incandescent material as high as 120 m above the crater rim. SERNAGEOMIN reported that at 1307 on 1 January a long-period earthquake was recorded but weather clouds prevented visual confirmation of possible emissions. The Alert Level remained at Yellow (the second lowest level on a four-color scale) and the public was warned that material could be ejected within 500 m of the crater. ONEMI maintained the Alert Level at Yellow (the middle level on a three-color scale) for the municipalities of Villarrica, Pucón (16 km N), Curarrehue, and the commune of Panguipulli.

Geological Summary. The glacier-covered Villarrica stratovolcano, in the northern Lakes District of central Chile, is ~15 km south of the city of Pucon. A 2-km-wide caldera that formed about 3,500 years ago is located at the base of the presently active, dominantly basaltic to basaltic-andesite cone at the NW margin of a 6-km-wide Pleistocene caldera. More than 30 scoria cones and fissure vents are present on 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. Eruptions documented since 1558 CE 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.

Sources: Servicio Geológico Minero Argentino (SEGEMAR), Servicio Nacional de Geología y Minería (SERNAGEOMIN), Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI), Proyecto Observación Villarrica Internet (POVI)