Servicio Nacional de Geología y Minería (SERNAGEOMIN) reported that an energetic explosion, more significant than the usual Strombolian events at Villarrica, ejected ballistics up to 500 m above the crater rim and as far as 1,400 m along the WNW flank (near the head of Correntoso valley) at 2104 on 10 July. The explosion also generated a column of ash and gas that reached over 600 m above the crater rim and was accompanied by a long-period (LP) earthquake. Following the explosion, the seismic energy levels remained low. However, infrasound observations suggest recurrent lava lake activity, with temporal variations in the level of activity. The volcano is currently exhibiting a heightened level of activity that exceeds its usual baseline. This includes signs of energetic instability that surpass the typical Strombolian activity usually recorded, with no precursory activity. The hazard zone radius was expanded from 500 to 2,000 m from the center of the crater as of 1130 on 12 July.

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 Nacional de Geología y Minería (SERNAGEOMIN), Servicio Geológico Minero Argentino (SEGEMAR)