POVI reported that increased seismicity, more intense crater incandescence, and a notable sulfur odor was noted at Villarrica during 18-19 December. Minor ash emissions rose to low heights above the crater rim on 22 December. The Alert Level remained at Yellow, the second lowest level on a four-color scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-color scale) for the municipalities of Villarrica, Pucón (16 km N), Curarrehue, the commune of Panguipulli, and the exclusion zone for the public of 500 m around the crater.

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