Soche

Geography & Climate

Soche is located in Ecuador, within the Northern Andean Volcanic Arc of the broader South America Volcanic Regions. Situated at 0.55° N, 77.58° W in the Northern Hemisphere, the volcano lies within a tropical climate zone. Standing at 3,955 meters above sea level, Soche towers above the alpine zone, where vegetation gives way to bare rock, snow, and ice for much of the year. The high elevation means the upper slopes experience significantly colder temperatures than surrounding lowlands. The volcanic landform is characterized as a composite, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Soche 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 Ecuador near Soche, 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 dacite, an intermediate to silica-rich volcanic rock. This composition typically produces more viscous magma, leading to more explosive eruptions with ash columns and pyroclastic flows. Andesitic and dacitic magmas build pressure before erupting, which is why volcanoes with this rock chemistry are often associated with Plinian-style eruptions that can send ash tens of kilometers into the atmosphere and disrupt aviation across entire regions.

Eruption History Summary

Soche has 1 recorded eruption in the geological database, spanning from 6650 BCE to 6650 BCE. The most powerful recorded event was a paroxysmal eruption with devastating regional consequences in 6650 BCE, reaching VEI 5 on the Volcanic Explosivity Index.

Significance

With a maximum recorded VEI of 5, Soche 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

Volcán el Soche, a small stratovolcano near the Colombia border, is the northernmost of a chain of Ecuadorian volcanoes east of the principal volcanic axis. This dominantly dacitic volcano was constructed over Paleozoic rocks and has a summit caldera open to the E. A major explosive eruption took place during the early Holocene at about 8600 years BP, depositing tephra NW into Colombia. The ejection of voluminous dacitic airfall pumice and pyroclastic flows was followed by the formation of two lava domes in the caldera.

— Smithsonian Institution, Global Volcanism Program