An overview of the methodologies to investigate on Na-Tech events triggered by volcanic ash fallouts

Amongst several natural phenomena (such as earthquakes, tsunamis, floods, tornadoes, hurricanes, windstorms, etc.), which can trigger Na-Tech (Natural-Technological) events, in this paper, attention has been paid to volcanic eruptions. The literature highlighted that volcanic eruptions can endanger human health and cause damage on critical structures, infrastructures, transport systems, chemical plants and lifelines. The impact of volcanic Na-Techs could also be significant for the environment. This paper gives a general overview on methodologies that are currently being developed to define the conditions leading to equipment failures or malfunctions due to volcanic ash fallout in chemical industry and wastewater treatment plant. A brief discussion about such potential Na-Tech scenarios will be provided with respect to an atmospheric storage tanks used to store liquid fuels (floating roof tank); then a potential scenario (roof tank fire) will be analysed to show severity of the technological incident initiated by the natural phenomenon.