Hudson, Cerro

Geography & Climate

Hudson, Cerro is located in Chile, within the Southern Andean Volcanic Arc of the broader South America Volcanic Regions. Situated at 45.90° S, 72.97° W in the Southern Hemisphere, the volcano lies within a temperate climate zone. With a summit elevation of 1,905 meters above sea level, Hudson, Cerro is a moderately sized peak that remains accessible to hikers and researchers for much of the year. 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

Hudson, Cerro 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 Hudson, Cerro, 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 basalt / picro-basalt, 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

Hudson, Cerro has 15 recorded eruptions in the geological database, spanning from 8010 BCE to 2011 CE. The most powerful recorded event was a colossal eruption capable of affecting global climate for years in 1890 BCE, reaching VEI 6 on the Volcanic Explosivity Index. Notable eruptions include 1991 CE (VEI 5), 1971 CE (VEI 3), 1890 BCE (VEI 6). This level of eruptive frequency indicates a persistently active volcanic system that warrants ongoing monitoring. With eruptive activity as recently as 2011 CE, Hudson, Cerro remains an actively monitored volcano.

Significance

Hudson, Cerro has produced at least one eruption of VEI 6 or higher, placing it among the most powerful volcanic systems on Earth. Eruptions of this magnitude inject massive quantities of sulfur dioxide into the stratosphere, affecting global climate by lowering average temperatures for one to three years after the event. With 15 recorded eruptions, Hudson, Cerro has a substantial eruptive history that provides valuable data for understanding volcanic behavior and assessing future hazards in the South America Volcanic Regions region. Given its recent activity, Hudson, Cerro is closely monitored by geological survey organizations to provide early warning of future unrest.

GVP Reference Summary

The ice-filled, 10-km-wide caldera of Cerro Hudson volcano was not recognized until its first 20th-century eruption in 1971. It is the southernmost volcano in the Chilean Andes, related to subduction of the Nazca plate beneath the South American plate. The massive volcano covers an area of 300 km2. The compound caldera is drained through a breach on its NW rim, which has been the source of mudflows down the Río de Los Huemeles. Two cinder cones occur N of the volcano and others occupy the SW and SE flanks. This volcano has been the source of several major Holocene explosive eruptions. An eruption about 6,700 years ago was one of the largest known in the southern Andes during the Holocene; another eruption about 3,600 years ago also produced more than 10 km3 of tephra. An eruption in 1991 formed a new 800-m-wide crater in the SW portion of the caldera.

— Smithsonian Institution, Global Volcanism Program