Tectonic faults accommodate plate motion through a spectrum of seismic and aseismic slip that spans a wide range of spatial and temporal scales. Understanding the mechanics and interplay between these deformation modes is central to seismotectonics, as it directly influences the seismic hazard assessment. Fluids play a key role by modulating effective stress and interacting with the evolving permeability and porosity of fault zones. Such hydro-mechanical and chemical feedbacks can promote transitions between stable and unstable slip, influencing earthquake nucleation and arrest as well as the occurrence of slow fault slip phenomena. Advancing our understanding of these processes is essential for constraining the physical conditions that control fault slip behaviors. We invite contributions from observational, experimental, geological, and theoretical studies that explore the diversity and interplay among seismic and aseismic slip phenomena in various tectonic environments. Key questions include: (1) How do fluids, fault properties, and loading conditions shape the distribution of seismic versus aseismic slip? (2) Can the same fault patches host different slip behaviors over time? (3) What systematic spatial or temporal relations exist between aseismic and seismic slip?
Nicolas Brantut