Geodynamical simulations cover a wide spatial and temporal range and are crucial to understand and assess the evolution of the Earth system. To enable computationally efficient modeling approaches that can account for potentially unknown subsurface properties, we present a surrogate modeling technique. This technique combines physics-based and machine-learning techniques to enable reliable predictions of geodynamical applications, as we illustrate for the case study of the Alpine Region.

A systematic laboratory experiment elucidates two-phase heat transport due to water flow in saturated porous media to understand thermal propagation in aquifers. Results reveal delayed thermal arrival in the solid phase, depending on grain size and flow velocity. Analytical modeling using standard local thermal equilibrium (LTE) and advanced local thermal non-equilibrium (LTNE) theory fails to describe temperature breakthrough curves, highlighting the need for more advanced numerical approaches.

We develop a simplified model which describes the geological geometry of the Vendenheim site, the solid and fluid properties were adapted from studies in the area. We implement compute the hydrothermal flow with a temperature dependent density and viscosity in a porous medium, in order to verify if a hydrothermal convective system is compatible with known observations at the Vendenheim site, and to get a better idea of the initial conditions of a model for an induced seismicity model. 

To operate aquifer thermal energy storages in a sustainable way, we located an artesian aquifer other than the aquifer storage in a research wellbore by analyzing the subsurface temperature as monitored with a fiber optic cable in three artesian flow tests. The positioning of the artesian aquifer was validated via numerical modelling. Analyses of the temperature data and numerical modelling enabled determining the profile of flow velocity, flow rate and the depth interval of inflow.

We compute a realistic three-dimensional model of the temperatures down to 75 km deep within the Earth, below the Caribbean Sea and northwestern South America. Using this, we estimate at which rock temperatures past earthquakes nucleated in the region and find that they agree with those derived from laboratory experiments of rock friction. We also analyse how the thermal state of the system affects the spatial distribution of seismicity in this region.