Increase in seismic energy, crack in the crater at Nevados de Chillán volcano, Chile

An increase in seismic energy was observed at Chilean Nevados de Chillán volcano in recent days, country's National Service of Geology and Mining (SERNAGEOMIN) reported Sunday, January 7, 2018. In addition, a crack was observed at the bottom of the new crater.

The eruptive activity at the volcano over the past 7 days was characterized by smaller explosions, pyroclastic ejection, sporadic incandescence and a new eruptive pulse on January 6. The activity was likely associated with the opening of above-mentioned crack, which now has a length of 30 – 40 m (100 – 130 feet), based on images taken during a recent overflight.

In the light of increased volcanic risk, Álvaro Miguieles, the governor of Ñuble, reminded the community that they are facing an active volcano, adding that existing evacuation plans have been updated.

The Civil Protection Service maintains an exclusion radius of 3 km (1.8 miles) around the volcano.

Geological summary

The compound volcano of Nevados de Chillán is one of the most active of the Central Andes of Chile. Three late-Pleistocene to Holocene stratovolcanoes were constructed along a NNW-SSE line within three nested Pleistocene calderas, which produced ignimbrite sheets extending more than 100 km (62 miles) into the Central Depression of Chile.

The largest stratovolcano, dominantly andesitic, 3212-m-high (10 500 feet) Cerro Blanco (Volcán Nevado), is located at the NW end of the group, and 3089-m-high (10 134 feet) Volcán Viejo (Volcán Chillán), which was the main active vent during the 17^th-19^th centuries, occupies the SE end. The new Volcán Nuevo lava-dome complex formed between 1906 and 1945 between the two volcanoes and grew to exceed Volcán Viejo in altitude. The Volcán Arrau dome complex was constructed SE of Volcán Nuevo between 1973 and 1986, eventually exceeding its height by 20 m (65 feet). (GVP)

Featured image credit: Sernageomin