<p>Historical strong earthquakes have triggered extensive landslide clusters in the Northern Mountains of Tianshui City (NMTS), China. With the increasing seismic activity in Northwest China, assessing the reactivation risk of these landslides under future seismic events and delineating their potential hazard zones have become critical scientific challenges. This study proposes a dynamic-process-based quantitative hazard assessment (QHA) framework for seismic-induced landslides. By integrating the Continuous-Discontinuous Element Method (CDEM) with engineering geological analogy, we accurately simulate the entire landslide process, including seismic wave propagation, progressive failure, movement, and deposition. Results reveal significant regional heterogeneity in failure mechanisms across the NMTS. The western zone is controlled by slope gradient, the central zone is dominated by the inclination of pre-existing slip surfaces, while the eastern zone is characterized by high-position failure and long-distance transport. Seismic amplification effects, influenced by topography and lithology, play a crucial role in landslide failure and runout dynamics. Based on simulation results, hazard assessment thresholds are established for unstable crown zones, deformation zones of old landslide masses, and reactivation zones at slope toes. These thresholds enable the generation of a quantitative hazard zonation map for the NMTS landslide clusters under rare earthquake scenario. This method provides a scientific basis for regional risk management and disaster mitigation planning.</p>