Deformation and rock failure in the subsurface could have significant socio-economic and environmental consequences, e.g., for tunnel safety, waste storage or hydrocarbon production. These consequences can be ameliorated through prior identification of subsurface regions that are at or close to yielding. Such identification requires remote sensing techniques and an understanding of the underlying characteristics of failure zones. The project will utilise elastic wave and acoustic emission data to remotely assess/monitor localised deformation and yielding in geomaterials (rocks and soils). This requires the integration of three main disciplines; geomechanics, rock physics and elastic wave methods. Individually these subjects are well established but through the integrated trans-disciplinary approaches, to be developed, it will be possible to answer questions that cannot be addressed by the individual subjects in isolation. Specifically such integration will enable the use of elastic-waves to assess internal 3D variations and evolution of deformation where direct observation is not possible. This applies to both the whole of the subsurface and laboratory experiments. The objectives will be achieved through integration and extension of existing theoretical/modelling procedures from the associated disciplines backed up by well-constrained laboratory experiments, to provide calibration and refinement of the methods, before more general application to in-situ remote sensing. The project will advance the science through interdisciplinary links but also, through such cross-linking, advancements will be made in each of the individual disciplines; e.g., extension of wave propagation theory/modelling ingeomaterials to consider evolving non-linear anisotropic elasto-plastic geomechanical states.