The session focuses on the study of anelastic properties of geomaterials and subsurface domains, mainly in the shallow or brittle regime. Anelastic deformation can arise from poroelasticity in porous and fractured rocks, friction, plasticity, thermodynamic disequilibrium and intrinsic viscoelasticity. We welcome laboratory experiments, numerical modeling, and field studies on dispersion and attenuation of seismic waves in rocks, magmas, saturating fluids and other geomaterials (e.g., methane hydrates and ice). The session should stimulate discussion among communities studying the non-elastic deformation of rocks at crustal temperature, pressure, strain and strain-rate regimes. The session goal is to allow such communities to benefit from one another’s contributions to expand the capability of upscaling observations from the laboratory and numerical simulations, improve the exploration and imaging of the subsurface, and comprehend geological processes.