Dr Rebecca Williams (@volcanologist.bsky.social)

Impacts-based analysis of disruption to airport operations by volcanic ashfall - Journal of Applied Volcanology Volcanic ash is a significant hazard to aviation due to its potential to cause physical impacts and disrupt aviation networks through airspace and airport closures. Until now, ashfall impacts on airport operations have received much less attention than airborne ash impacts on aircraft and aviation. The time and resources taken to remove ashfall from runways and airport infrastructure can cause extended disruption to the aviation network beyond the presence of ash in the atmosphere. Using publicly available information, we have compiled a global dataset of 334 volcano-related airport impact events between 1944 and 2024. The dataset includes events at 141 unique airports in 44 different countries and territories, caused by eruptions from 73 different volcanoes. The countries with the most events are Indonesia (52), Mexico (27), and New Zealand (27), and the most impacted airports are Catania-Fontanarossa International Airport (20), Puebla International Airport (15), and La Nubia Airport (12). The volcanoes responsible for the most airport impact events (besides Eyjafjallajökull) are Etna (24), Soufriere Hills (22), and Popocatépetl (22). We used 74 data-rich, ashfall-induced events from this dataset to categorise ashfall impacts into five states of closure: <1 day, 1–2 days, > 2–7 days, > 1 week (finite), and permanent, and present fragility curves for each state. Data points are concentrated between 0.1- and 100-mm thickness such that fragility curve uncertainties are greatest at the smaller (< 0.1 mm) and larger (> 100 mm) thicknesses. The curves show that there is an > 80% probability of airport closure of any duration even for trace (defined here as 0.1 mm) amounts of ashfall. Closures of more than one day under trace ashfall are much more probable than closures lasting more than two days (30% vs. 6%, respectively), and once ashfall of 10 mm thickness is reached closures of more than two days are highly probable (> 85%). The development of continuous fragility curves from empirical airport closure data represents an advance that will prove useful for hazard management and long-term forecasting closure at airports. To illustrate the potential impacts of varying closure durations on flights and passengers, we provide a case study of the simulated closure of Ninoy Aquino International Airport in the Philippines. In addition to ashfall thickness, closure duration is affected by airport or national emergency management policies, resources available (personnel and equipment), and environmental conditions. This dataset and the derived curves provide a starting point and global evidence base for better understanding the impact of volcanic ashfall on airport operations. https://doi.org/10.1186/s13617-026-00164-9