We present the first application of PP-precursor analysis to image upper-mantle discontinuities beneath the Central Alborz region, focusing on the area around Mount Damavand, north-central Iran. We analyze teleseismic data (M>5.5) from 10 permanent broadband stations using two independent earthquake datasets from the Japan and Sumatra/Indonesia regions, providing distinct azimuthal sampling of the upper mantle. For the Japan dataset, reflections corresponding to the 410- and 520-km discontinuities are identified at depths of ~400 km and ~530 km, respectively, while the 660-km discontinuity is not clearly resolved and a weak arrival near ~640 km is present. The Sumatra dataset reveals all three discontinuities at ~440 km, ~500 km, and ~660 km depth. Mean depths averaged across both datasets are estimated at 420±20 km, 515±15 km, and 650±20 km for the 410-, 520-, and 660-km discontinuities, respectively. Systematic depth differences between datasets indicate lateral thermal and/or compositional heterogeneity and possible dip of the mantle transition zone (MTZ) boundaries. When integrated with independent geophysical constraints, including the documented absence of a crustal root beneath the Alborz, our results support a geodynamic model in which deep-seated thermal and dynamical processes, including lithospheric delamination and asthenospheric upwelling, play a fundamental role in sustaining the anomalous topography and ongoing magmatic activity at Mount Damavand. This study demonstrates the utility of PP-precursor stacking for constraining MTZ structure and linking discontinuity topography to geodynamic processes in complex collisional settings.