The lifecycle of volcanic ash: advances and ongoing challenges

Abstract Explosive volcanic eruptions can produce vast amounts of ash made up mainly fragments magmatic glass, country rock and minerals < 2 mm in size. Ash particles forming from magma fragmentation are generated by several processes when brittle response accommodates (local) deformation stress that exceeds the capability bulk material to respond viscous flow. These span a wide range temperatures, occur inside or outside edifice involve all melt compositions. is then dispersed atmospheric over large distances have global distributions. repeatedly drawn focus studying ash. The continued occurrence such worldwide their widespread impacts motivates study chemical physical involved lifecycle (e.g. fragmentation, particle aggregation), as well immediate long-term effects water air pollution, soil fertilization) consequences environmental, economic, social) associated with ashfall. In this perspectives article, we reflect on progress last two decades understanding (1) generation; (2) dispersion, sedimentation erosion; (3) atmosphere, hydrosphere, biosphere modern infrastructure. Finally, discuss open questions future challenges.