An exploration of potential magma propagation pathways within Santorini volcano, Greece

Shallow-crustal magma transport occurs mainly via dykes and inclined sheets, which may or may not reach the surface to erupt. Originating from various magma sources, dyke propagation is primarily controlled by magma overpressure, magma rheology, local stress fields and the mechanical properties of the host rock, shaping the complex spatio-temporal evolution of transcrustal plumbing systems. Here, we use finite element method numerical models to investigate how shallow-crust heterogeneities influence dyke pathways at Santorini volcano (Greece). In our models, subvertical dykes predominantly ascend from the roofs of sill-like magma chambers, whereas inclined sheets emerge from lateral chamber ends and occasionally reach the surface beyond the caldera. Our results show that layered systems with contrasting mechanical properties and vertically stacked magma storage promote stress rotations that favour dyke and sheet arrest. The initial site of dyke injection strongly controls whether magma propagates vertically or along an inclined trajectory, emphasizing the role of chamber depth, crustal heterogeneity, and regional stress in magma pathways and recharge locations. This study enhances our understanding of potential shallow and deep magma pathways providing new insights into future unrest episodes at Santorini volcano.