TTE150

Modelamiento de lahares para la determinación de las zonas de inundación …

ABSTRACT

The Llaima volcano, one of the most active volcanoes in Chile, has more than 50 eruptions in historical times. Among its dangers, the most common is related to the generation of lahars, which are mixed flows of water and debris of volcanic origin that in the past have affected nearby communities such as Melipeuco, Cherquenco, and Curacautín. This phenomenon occurs due to an eruptive style that usually involves sources such as lava flows, which partially melt a section of the large glaciers present in the volcano. Given that lahars can be very destructive and dangerous, it becomes very important to understand their dynamics and build potential hazard scenarios that can complement the existing volcanic hazard map through flood maps. In this work, the possible lahars of the Llaima volcano are modeled according to various eruptive scenarios, in order to generate a matrix of threat scenarios regarding these debris flows. The modeling was carried out using the LaharFlow software, which represents an important quantitative leap in the quality of the simulations compared to the more widely used LaharZ. We have calibrated the simulations with historical lahar advance data from the 2008 eruption of the volcano, being able to reproduce its dynamics and extent very well. The results show the different flood areas in the different basins and how the different emission points can affect nearby towns such as Melipeuco, the Conguillío National Park, and the main tourist centers of the Llaima volcano. The application of the simulation in the most severe scenarios allowed us to identify that eruptions on the southern flank of the volcano could severely affect the population of Melipeuco, near the Pangueco and Manzano sectors, and floods of catastrophic characteristics in eruptions on the western flank in the basin, of the Calbuco River arriving with great power to the town of Cherquenco and possibly extending to Vilcún with less energy. Our results present a basis for more precisely detailing the associated hazards of the volcano and more accurately complement existing data on the volcano and raise awareness for the community. Keywords: Lahars, Llaima, Numerical Simulations, Hazard Scenarios

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