RAPID: The 2012-2013 eruptions of Copahue volcano, Argentina

Wesleyan University, Middletown CT

Investigators

Abstract

Volcanic eruptions impact global climate, geothermal energy is derived from volcanic heat, and many ore bodies are formed through volcanic processes. Active volcanism provides a direct means to study how our planet functions. Copahue volcano in Argentina (37.8 oS, 71 oW) started a new eruption on December 22, 2012 and is still active at low level today. This volcano emits compositionally extreme hydrothermal fluids that derive directly from a very acid and hot magmato-hydrothermal system at 1-2 km depth. Such fluids are thought to be responsible for epithermal ore deposits, eg. gold, silver and lead and may overly systems that form porphyry ore bodies. The composition of these fluids changes with the state of activity of the volcano: shallow intrusions lead to hotter and more concentrated fluids that are expelled into the ambient and acidify local rivers and lakes. Monitoring the composition of such streams during a period of volcanic activity aids in developing tools for eruption forecasting. Data collected on fluids during the 2000 eruption of Copahue suggested several parameters that indicate the intrusion of shallow magma prior to an eruption. The 2012-2013 eruptive period provides an ideal venue to test and refine these ideas. A large glacial lake that is stratified during the austral summer contains compositional information of the pre-eruptive fluids in the bottom waters, whereas the surface waters represent recent inputs. It is imperative to sample the lake prior to its seasonal overturn in late April, when the water column homogenizes and all detailed information is lost. A workshop with scientists from Argentina, Italy and the USA is convened for March 2013 to discuss the eruption, its hazards and monitoring efforts, and US scientists with an extensive research record on Copahue should participate and contribute to this event. The research activities will contribute to the science of eruption monitoring and forecasting, which is beneficial for many people living on volcanoes worldwide. It also promotes collaboration between local Argentinian and US scientists. The local authorities plan to establish a small volcano observatory near Copahue, but data are needed to make the best possible choices of monitoring parameters. Besides the bilateral collaboration, two female US students (one undergraduate, one graduate) will collect samples on site and analyze those at Wesleyan University for their senior and MA theses. Training of US students in research on active volcanoes is important to keep the USA in a scientific leadership position with respect to assessments of both natural hazards and formation of natural resources.