Synthetic benchmarking of concentrated pyroclastic current models

Validation and benchmarking of pyroclastic current (PC) models is required to evaluate their performance reliability for hazard assessment. Here, we present results a initiative built four commonly used assess concentrated PC hazard: SHALTOP, TITAN2D, VolcFlow, IMEX_SfloW2D. The benchmark focuses on the simulation channelized flows with similar source conditions over five different synthetic channel geometries: (1) flat incline plane, (2) sharp 45° bend, (3) straight break-in-slope, (4) an obstacle, (5) constriction. Several outputs from 60 simulations using three initial volume fluxes were investigated when simulating valley-confined kinematics, including overflows induced by topographic changes. Quantification differences obtained between model at t = 100 s allowed us identify issues Voellmy-Salm implementation TITAN2D small discrepancies other codes that are either due various curvature velocity formulations and/or numerical frameworks. Benchmark also in agreement field observations natural PCs: sudden change geometries combined high-volume flux key generate overflows. benchmarks proved be useful evaluating performance, needed overarching goal provide interpretation framework volcanic mass flow assessment studies geoscience community.