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

William Marsh Rice University, Houston TX

Investigators

Abstract

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. Achieving this goal is contingent upon the integration of observations through reliable physics-based models that have been tested in their predictive capabilities. This is the project's principal focus and it will advance 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. Furthermore, 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 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 over some range of identical conditions effusive or explosive activity is possible and with potentially rapid transitions from one to the other. One goal of the project is the assessment of conditions resulting in transitions in eruptive activity in order to test this explosive-effusive bistability hypothesis. Moreover, 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. The project as such is multi-disciplinary and encompasses geochemistry, petrology and geodesy, in addition to numerical simulation of magma storage and eruption. As a consequence, the project is also multi-institutional and in addition to existing observations, new data will be acquired through efforts led by the other collaborating institutions. The portion of the project that Rice University will focus on - in collaboration with the other institutions - are the numerical simulation and the integration of the different types of observational data. 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.