Fault systems accommodate deformation through a wide and complex spectrum of slip behaviors, ranging from aseismic creep and episodic slow-slip events to earthquakes. Field and laboratory observations, and seismological and geodetic data along with numerical and analogue modelling show that slip behavior of faults is governed by the interplay of multiple factors acting over a wide range of spatial (from nanometers to kilometers) and temporal (from milliseconds to million years) scales. These factors include tectonic setting, interactions between fault network patterns, structural and geometrical complexity, mechanical and rheological heterogeneities, slip history, fluid pressure and chemistry, and temperature. Despite significant advances, how these interconnected factors collectively control the deformation partitioning within fault systems and the resulting seismic or aseismic behavior of individual fault segments and patches remains a fundamental and unresolved challenge, with major implications for understanding the seismic cycle. This session invites contributions that investigate how fault zones and fault systems accommodate deformation using multidisciplinary and multiscale approaches. We particularly encourage studies based on field and microstructural analyses of exhumed faults, laboratory experiments, geochemical characterization of fluids, seismological and geodetic observations of active faults, and numerical and analogue modelling. Our aim is to foster discussion on fault geometrical complexity and slip behavior, from the scale of entire fault systems down to the physico-chemical processes controlling local fault properties, with implications for understanding complex earthquake sequences and improving seismic hazard assessment in seismically active regions.
Corentin Noël