Collaborative Research: Chamber or Conduit - Constraining Explosive Through Effusive Eruption at Cordon Caulle, Chile 2011/12

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Volcanic eruptions pose one of the principal hazards at tectonically active continental margins, such as the Pacific northwestern United States, which are of ever increasing economic and existential importance to expanding populations. The project will enhance knowledge of the conditions that lead to eruptions of silica-rich magmas, which can be large and impactful. It will boost understanding of the fundamental processes that determine the progression of volcanic eruptions, from inception to cessation, which remains difficult to forecast. Consequently, the project transcends the purely academic and is societally relevant by advancing natural hazard assessment capabilities. The project supports education by enabling the interdisciplinary training of graduate and undergraduate students as well as a postdoctoral scholar, thus contributing to the development of a diverse and globally competitive workforce.The project's objective is to advance fundamental knowledge of how volcanoes work by simulating a volcanic eruption from initial explosive activity through lava effusion, to termination of the eruption and post-eruptive inflation, using the 2011/12 Cordon Caulle eruption in Chile as a case study. For this eruption the run-up, the syn-eruptive evolution, and the post-eruptive reconfiguration of the volcanic system were documented in unprecedented detail. The project is multi-disciplinary and multi-institutional. It encompasses geochemistry, petrology and geodesy, in addition to numerical simulation of magma storage and eruption. At the University of Nevada, Reno, the focus will be on constraining magma ascent rates and volatile budgets for the 2011/12 Cordon Caulle eruption using mineral and melt-based techniques. Furthermore, the contribution of mafic recharge to the eruptive activity will be explored with respect to the volatile budget. The geochemical data will be integrated with existing data, additional geodetic observations and numerical simulations in collaboration with the other institutions. The eruption was initially explosive and over time eruption rates decreased with activity shifting from purely explosive to effusive, resulting in the formation of a large lava flow and shallow laccolith. The current view about these types of eruptions is that effusive or explosive activity is possible under otherwise identical conditions and with potentially rapid transitions from one to the other. A goal of the project is the assessment of conditions resulting in transitions in eruptive activity in order to test this explosive-effusive bistability hypothesis. Rapid post-eruptive inflation was observed and a further goal is to assess the extent to which the system has been driven back toward a critical state. These goals will be achieved by integrating the different observational data within extensive physics-based model simulations that will lead to improvements in model reliability and further our understanding of underlying processes at Cordon Caulle and similar hazardous volcanic systems elsewhere.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.