Regions of the Earth deforming at sub-centimetre rates show a broad range of behaviour. Some areas, such as the Dead Sea Transform, show well-defined plate boundaries, but in others, such as the compressional portion of the North American-Eurasian plate boundary in Northeastern Russia, we find wide zones of diffuse deformation, microplates, and no distinct boundary. The picture becomes more varied still when considering intraplate regions, where deformation varies in space and time, as for instance in North China where in a 2000 year history of seismicity, no two large earthquakes occurred on the same fault. Similarly, seismicity in midcontinental North America and Australia has wandered over thousands of kilometres between different fault systems over time. The geologic past may also contain many examples of enigmatic, and likely very slow accumulations of strain over millions of years. For instance, in the Late Cretaceous, the western central European platform was affected by a complicated zone of deformation that included the intraplate uplift of the Harz mountains, the deformation of the Thuringian Forest, and inversion of many older rift structures. Such deformation raises important issues both for understanding lithospheric tectonics and assessing the resulting earthquake hazards.

This session aims to explore similarities and differences between slowly deforming regions of the Earth's crust, drawing on a wide range of examples both from the present and the geological past. It also invites contributions from theoretical and numerical modelling studies of slow deforming regions and their evolution.