How will the next eruption in Tenerife affect aviation?

During a volcanic eruption, one of the most relevant threat for civil aviation is the dispersion of volcanic ash in the atmosphere. All the aircraft are susceptible to suffer damages from volcanic ash even at low concentrations. The economy of Canary Islands (Spain) strongly depends on tourism, so it is of fundamental importance to estimate the consequences of a possible eruptive scenario of the air traffic in the archipelago and consequently on the tourism. We made an exhaustive study about the impact of volcanic ashes on aviation for one of the most important islands in the archipelago: Tenerife.

We developed a large set of numerical simulations of small-magnitude eruptions in Tenerife, which are the most probable eruptive scenario in this island. Our main goal is to develop a probabilistic approach to evaluate the airports most affected by dispersion and fallout of volcanic ash. We carried out more than a thousand simulations with the software FALL3D using supercomputing facilities of Teide-HPC from the Instituto Tecnológico y de Energías Renovables (ITER). In order to model the small-magnitude eruptions, we calculated datasets of total mass of volcanic ash erupted and eruption lengths using a bivariate empirical probability density function obtained using Kernel Density Estimation (KDE) from data of historical eruptions in Tenerife. The vent positions were selected following the density of vents related to Holocene eruptions. Granulometries were chosen following Bi-Gaussian distribution of particle size ranging from Φ=-1 to Φ=12, where Φ=-log₂d (diameter in mm). The number of eruptive phases within each eruption is selected randomly. We have split equally the total eruptive duration into these eruptive phases and we set a gaussian distribution in the centre of each division. After that, the intersection between each eruptive phase is chosen taking into account these gaussian distributions to have eruptive phases with different duration.

All the simulations are coupled with ERA-Interim meteorological reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF). We have implemented a probabilistic procedure to map in 3D the hazard associated to volcanic ash. For this purpose, we calculated concentration percentiles (P₂₅, P₅₀ and P₇₅) and time intervals of high concentrations of volcanic ash to evaluate the hazard of suspended ash in the volume surrounding the major airports in Tenerife.