Gradually increasing activity at Villarrica since 15 November prompted OVDAS-SERNAGEOMIN to raise the Alert Level to Yellow (the second lowest level on a four-color scale) on 5 December, and warn the public to stay outside of a 1-km radius around the crater.
Increased activity was characterized by recorded volcano-tectonic earthquakes, increased thermal anomalies identified in satellite data, and increased lava-lake activity.
The infrasound network, photos, and field observations confirmed a higher lake level and explosions that were ejecting material deposited in the crater area.
Lava fountains 150 m high were documented by POVI during the second half of November.
Sources: Proyecto Observación Villarrica Internet (POVI),Servicio Nacional de Geología y Minería (SERNAGEOMIN)