Sollipulli

Geography & Climate

Sollipulli is located in Chile, within the Southern Andean Volcanic Arc of the broader South America Volcanic Regions. Situated at 38.97° S, 71.52° W in the Southern Hemisphere, the volcano lies within a temperate climate zone. At 2,282 meters above sea level, Sollipulli rises above the surrounding terrain into montane or subalpine conditions. The elevation creates distinct ecological zones along its flanks, from forested lower slopes to exposed rocky terrain near the summit. The volcanic landform is characterized as a caldera, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Sollipulli sits in a subduction zone, where one tectonic plate dives beneath another, creating intense heat and pressure that generates magma. Subduction zones are responsible for many of the world's most explosive volcanoes and deadliest eruptions. For communities in Chile near Sollipulli, this tectonic setting means the volcano is capable of producing powerful explosive eruptions, pyroclastic flows, and lahars that can threaten populated areas within tens of kilometers of the summit. The dominant rock type is andesite / basaltic andesite, a dark, fine-grained volcanic rock that forms from rapidly cooling, low-viscosity lava. Basaltic eruptions tend to be less explosive and produce fluid lava flows that can travel long distances. While less immediately dangerous than explosive eruptions, basaltic lava flows can destroy structures and infrastructure in their path, and volcanic gases released during these eruptions can affect air quality over a wide area.

Eruption History Summary

Sollipulli has 2 recorded eruptions in the geological database, spanning from 920 BCE to 1240 CE. The most powerful recorded event was a paroxysmal eruption with devastating regional consequences in 920 BCE, reaching VEI 5 on the Volcanic Explosivity Index. These eruptions span roughly 2,160 years of volcanic history.

Significance

With a maximum recorded VEI of 5, Sollipulli has demonstrated the capacity for paroxysmal eruptions comparable to the 1980 eruption of Mount St. Helens. Eruptions of this scale can devastate areas within 20-30 kilometers and produce ash fall that disrupts aviation and agriculture across hundreds of kilometers.

GVP Reference Summary

The 4-km-wide, glacier-filled Sollipulli caldera lies E of the Pleistocene Nevados de Sollipulli complex. Major silicic pyroclastic rocks associated with caldera formation have not been found; it may have a non-explosive origin. Post-caldera eruptions have been focused along the caldera walls and have increased its height. A series of dacitic lava domes lines the E and S caldera rims. The 1-km-wide Alpehué crater, which cuts the SW rim, was the source of a large Plinian eruption 2900 years before present (BP). Explosion craters and scoria cones are found on the outer flanks. Two N-flank cones produced lava flows during the latest documented activity about 700 years BP (Naranjo et al., 1993). This low-profile volcano is less prominent than its neighbors Llaima and Villarrica, but its explosive history makes it a potentially hazardous volcanic center.

— Smithsonian Institution, Global Volcanism Program