Using multi-model and coupled model based simulations and UQ for analysis of volcanic hazards

San Francisco

This presentation will focus on the systematic use of multiple models (resulting from different assumptions on rheologies for the mass flows resulting from volcanic debris avalanches), coupled models (resulting from the coupling of eruption models and plume/transport models) and UQ for analysis of volcanic hazards. Since, the best rheology for modeling mass flows from volcanic activity is difficult to determine a number of rheologies have been proposed. These include the single phase Mohr-Coulomb models, Voellmy-Salm and Pouliquen-Forterre models or the more complicated two-phase models of Pitman-Le. We will discuss an approach based on using our newly released TITAN2D v4.0 (vhub.org) which allows seamless access to all four options for the same site in the same computational workflow. We introduce the use of simple Bayesian model averaging for hazard analysis based on an identified quantity of interest. In the second part of the presentation we will discuss the use of coupled models - a situation needed by the sequence of eruption, plume development and transport that must be understood for analyzing the hazards from volcanic ash transport. Both of these problems will be embedded in an UQ framework that attempts to quantify the probabilities of specific hazard criteria being met.