Misti, El

Geography & Climate

Misti, El is located in Peru, within the Central Andean Volcanic Arc of the broader South America Volcanic Regions. Situated at 16.30° S, 71.41° W in the Southern Hemisphere, the volcano lies within a tropical climate zone. At 5,793 meters above sea level, Misti, El reaches well into the permanent snow and ice zone. Glaciers and snowpack on the upper slopes create the potential for lahars — destructive volcanic mudflows — during eruptions, as heat rapidly melts ice and snow. 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

Misti, El 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 Peru near Misti, El, 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

Misti, El has 20 recorded eruptions in the geological database, spanning from 4020 BCE to 1985 CE. The most powerful recorded event was a cataclysmic eruption with ash columns reaching the stratosphere in 80 BCE, reaching VEI 4 on the Volcanic Explosivity Index. With an average interval of roughly 300 years between eruptions over a span of 6,005 years, this is one of the more frequently active volcanoes in the database. This persistent activity suggests a robust and well-supplied magma system beneath the volcano. The most recent eruption in 1985 CE places this volcano within the modern era of volcanological observation.

Significance

With a maximum recorded VEI of 4, Misti, El has demonstrated the capacity for significant explosive eruptions that can impact regional aviation, agriculture, and communities tens of kilometers from the summit. VEI 4 eruptions produce ash columns reaching 15-25 kilometers into the atmosphere. Its 20 recorded eruptions make it one of the most prolific volcanoes in our database, reflecting a persistent and well-documented eruptive history that has provided volcanologists with extensive data for understanding eruption patterns and forecasting future activity. Given its recent activity, Misti, El is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

El Misti is a symmetrical andesitic stratovolcano with nested summit craters immediately NE of the city of Arequipa, Peru. Eruptions from the active cone began about 13,700 and 11,300 years ago, within a 1.5 x 2 km caldera that underwent collapse about 50,000 years ago. A large scoria cone has grown with the 830-m-wide outer summit crater. At least 20 tephra-fall deposits and numerous pyroclastic-flow deposits have been documented during the past 50,000 years, including a pyroclastic flow that traveled 12 km S about 2,000 years ago. The most recent activity has been dominantly pyroclastic, and strong winds have formed a parabolic dune field of volcanic ash extending up to 20 km downwind. An eruption in the 15th century affected nearby Inca inhabitants. Some reported eruptions may represent increased fumarolic activity.

— Smithsonian Institution, Global Volcanism Program