Subduction zones generate numerous natural hazards, including volcanism, earthquakes and tsunamis, and shape the landscape through a series of processes lasting from seconds to millions of years. Their dynamics are driven by complex feedbacks between stress, strain, rock transformation and fluid migration along and across the plate interface, from shallow to deep environments. Despite their utmost importance, the intricate time-sensitive thermo–hydro–mechanical–chemical (THMC-t) processes remain largely puzzling. This is essentially due to the complexity of integrating observations across multiple spatial, magnification and temporal scales (from the nanoscale and the grain boundary size to the plate interface, and from seconds to millions of years).

Our session aims, therefore, at gathering recent advancements in observatory techniques, monitoring and high-resolution imaging of i) the plate interface kinematics, ii) the accretionary wedge, iii) the subducting slab, and iv) the mantle wedge in active and fossil subduction interfaces. This includes studies from a wide range of disciplines, such as seismology and geodesy, geodynamics, marine geosciences, field-based petrology and geochemistry and microstructure, rock mechanics and numerical modelling. We particularly encourage initiatives that foster collaboration between communities to achieve a comprehensive understanding of subduction systems through space and time.