Chilean authorities have raised the Alert Level for Villarrica volcano to Yellow (the second lowest level on a four-color scale) on December 5, 2017. The last eruptive episode of this volcano started on December 2 (± 7 days), 2014 and ended on October 15, 2017. It had Volcanic Explosivity Index of 1 (on a scale of 7)
OVDAS-SERNAGEOMIN raised the alert level following gradually increasing activity observed at the volcano since November 15, 2017. Increased activity was characterized by 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 (490 feet) high were documented by POVI during the second half of November.
The public is warned to stay outside of a 1-km radius (0.6 miles) around the crater.
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 (3.7 miles) caldera formed during the late Pleistocene. A 2-km-wide (1.24 miles) caldera that formed about 3 500 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 (12.4 miles) from the volcano were produced during the Holocene. Lava flows up to 18 km (11.2 miles) 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 (15.4 mi2) of the volcano, and lahars have damaged towns on its flanks. (GVP)
Featured image: Near-vertical view into the crater of Villarrica volcano. Credit: Jean-Claude Tanguy, Institute de Physique du Globe de Paris