In the development and production of high-temperature geothermal resources, large induced gradients in pressure and temperature during injection operations results in complex dynamics. This includes boiling of geothermal fluids and deformation of the fractured rock, dynamics that are currently not well understood. This provides a core motivation as well as challenging test cases for the mathematical and numerical developments in the MaPSI project. MaPSI has as its main objective to provide mathematical models and simulation technology required to assess subsurface process-structure interaction in the context of hydraulic and thermal stimulation in development and production of high-temperature geothermal resources. This will be achieved by a highly novel and timely research programme which will: - Combine new techniques with recently developed methodology by my own research group to develop unprecedented mathematical and numerical approaches to enable modelling of multiphase flow and phase-change in thermo-poroelastic media with fractures that may slip, deform and propagate; - Advance competences in the main scientific fields involved; and - Improve understanding of coupled processes in development and production of high-temperature geothermal systems towards sustainable exploitation of the resource. The project will provide new mathematical and numerical models along with open-source software that have capabilities in modelling of coupled process-structure interaction in fractured porous media that greatly exceed those of existing platforms. Specific case-studies will assess process-structure interactions for development and production operations in high-temperature geothermal systems, including superheated and supercritical regimes, providing timely contributions to further developments of these resources.