Chiles-Cerro Negro

Geography & Climate

Chiles-Cerro Negro is located in Colombia-Ecuador, within the Northern Andean Volcanic Arc of the broader South America Volcanic Regions. Situated at 0.82° N, 77.94° W in the Northern Hemisphere, the volcano lies within a tropical climate zone. Standing at 4,698 meters above sea level, Chiles-Cerro Negro 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

Chiles-Cerro Negro 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 Colombia-Ecuador near Chiles-Cerro Negro, 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

Chiles-Cerro Negro has 1 recorded eruption in the geological database, spanning from 1936 CE to 1936 CE. The most powerful recorded event was an explosive event producing ash plumes up to several kilometers in 1936 CE, reaching VEI 2 on the Volcanic Explosivity Index. The most recent eruption in 1936 CE places this volcano within the modern era of volcanological observation.

GVP Reference Summary

The Chiles-Cerro Negro volcanic complex includes both the Pleistocene Chiles and the Cerro Negro de Mayasquer stratovolcanoes astride the Colombia-Ecuador border. Cerro Negro has a caldera open to the west, with andesitic and dacitic lava flows of possible Holocene age (Hall 1992, pers. comm.) and solfataras on the shore of a small crater lake. An eruption reported in 1936 may have been from Reventador (Catalog of Active Volcanoes of the World). The higher, glacier-covered summit of Chiles, about 4 km ESE of Cerro Negro, last erupted about 160,000 years ago, but it has a caldera open to the north with hot springs and an active hydrothermal system on its eastern flank.

— Smithsonian Institution, Global Volcanism Program