Ruiz, Nevado del

Geography & Climate

Ruiz, Nevado del is located in Colombia, within the Northern Andean Volcanic Arc of the broader South America Volcanic Regions. Situated at 4.89° N, 75.32° W in the Northern Hemisphere, the volcano lies within a tropical climate zone. At 5,279 meters above sea level, Ruiz, Nevado del 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

Ruiz, Nevado del 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 near Ruiz, Nevado del, 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

Ruiz, Nevado del has 20 recorded eruptions in the geological database, spanning from 350 CE to 2014 CE. The most powerful recorded event was a cataclysmic eruption with ash columns reaching the stratosphere in 1595 CE, reaching VEI 4 on the Volcanic Explosivity Index. Notable eruptions include 2012 CE (VEI 3), 1985 CE (VEI 3), 1845 CE (VEI 3). With an average interval of roughly 83 years between eruptions over a span of 1,664 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. With eruptive activity as recently as 2014 CE, Ruiz, Nevado del remains an actively monitored volcano.

Significance

With a maximum recorded VEI of 4, Ruiz, Nevado del 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, Ruiz, Nevado del is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers more than 200 km2. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the caldera of an older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. The prominent La Olleta pyroclastic cone located on the SW flank may also have been active in historical time. Steep headwalls of massive landslides cut the flanks. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption.

— Smithsonian Institution, Global Volcanism Program