Numerical modeling of volcanic slope instability and related hazards at Pacaya Volcano, Guatemala

Document Type

Conference Proceeding

Publication Date

6-24-2012

Department

Department of Geological and Mining Engineering and Sciences

Abstract

This study uses numerical modeling to determine the possibility of an edifice collapse at the active Pacaya Volcano in Guatemala. Stability analyses using the Limit Equilibrium Method (LEM) and the Finite Element Method (FEM) were performed on the south-western flank using the physical-mechanical material properties of Pacaya's intact rocks and rock mass characteristics based on field observations and laboratory tests. The Hoek and Brown failure criterion was used to calculate the friction angle, cohesion, and rock mass parameters in a determined stress range. Volcanic instability was assessed based on the variability of the Factor of Safety and Shear Strength Reduction using deterministic, sensitivity, and probabilistic analyses considering static conditions. Results indicate the volcanic slope is stable under gravity alone, but the possible presence of a layer of pyroclastics significantly reduces the stability of the slope. Future work will focus on verifying the presence of this layer and evaluating the effect of external loading mechanisms such as earthquake load and magma pressure on the slope stability at Pacaya.

Publication Title

46th US Rock Mechanics / Geomechanics Symposium 2012

ISBN

9781622765140

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