Integrating Fault Stability and Stress Analysis in Ethiopian Rift Geothermal Field

The Tulu Moye geothermal field in the actively deforming Main Ethiopian Rift presents substantial potential for renewable energy production, but interactions between fault systems, hydrothermal fluids, and tectonic activity pose challenges for sustainable exploitation. Here we investigate fault stability and reactivation risks under current stress conditions and geothermal activities. By combining stress inversion of earthquake focal mechanisms with structural mapping, we assess fault reactivation potential through slip tendency, dilation tendency, and fracture susceptibility analyses. We evaluate critical pore pressures and stress magnitudes required for rock failure using Monte Carlo simulations. Results indicate that several faults are critically stressed, with modest pore pressure increase (3–5 MPa) potentially triggering fault slip and induced seismicity at 2 km depth. These findings align with observed microseismicity patterns linked to hydrothermal fluid flow, which enhances reservoir permeability but increases fault reactivation risks. This study provides a framework for assessing fault stability and managing risks in geothermal systems in tectonically active regions.