Quantitative Assessment of Active Fault Movement Potential Using FMP Model: a Case Study from the Central Iran Plateau

Seismically active faults are key tectonic structures controlling earthquake generation in intraplate settings. In the structurally complex Ashin–Biabanak corridor of Central Iran, fault reactivation potential remains underexplored due to low historical seismicity and limited predictive capacity of traditional qualitative methods. This study applies the Fault Movement Potential (FMP) model to quantify the reactivation likelihood of major faults in the Anarak region based on their geometric relationship with the regional principal stress direction, specifically the deviation angle (β). Structural data from 18 field stations were analyzed to calculate β relative to the dominant N10°E stress axis. These values were incorporated into a normalized FMP function, with further evaluation using microseismic data from BHRC (2014) within a 3-kilometer buffer around fault segments. Results show that faults with β < 20° exhibited the highest FMP values (>0.8) and correlated with microseismic clusters, while faults with β > 60° showed FMP values <0.2. No significant correlation was found between fault length and FMP, and strike-slip faults had slightly higher FMP values than reverse faults. A strong negative correlation (r ≈ –0.88) was observed between β and FMP. These findings highlight fault orientation relative to stress as the primary control on reactivation potential, surpassing fault length and kinematic type. The integration of field observations with FMP modeling offers a spatially resolved and quantitative approach for seismic hazard assessment in low-seismicity, tectonically stable regions.