Crustal and Upper Mantle Structure of the Pamir‐Hindu Kush Region Revealed by Precursors to Teleseismic sS and pP Phases

Abstract The Pamir‐Hindu Kush region, situated within the Alpine‐Himalayan orogenic belt, provides a natural laboratory for studying continental collision processes. Recent deployments of seismic arrays in this region have greatly improved our understanding of its crustal and lithospheric structure from tomographic and receiver function studies. However, strong temporal variability in station coverage limits sampling in individual subregions to short, generally non‐overlapping periods, hindering resolution of lithospheric‐scale structures across the region. Here, we analyze teleseismic depth phases (sS/pP) and their precursors from well‐distributed intermediate‐depth earthquakes beneath the Pamir‐Hindu Kush to improve spatial coverage of the lithospheric structure and better constrain the Moho and other interfaces above the earthquakes. Waveform inversion indicates that the crust beneath the southwestern Pamir is ∼80 km thick. Beneath the Tajik Basin, the Moho is at a depth of ∼45 km. Along its eastern margin, the lower boundary of a delaminated crustal layer is observed at 70 km depth. The ∼80 km Moho beneath the southwestern Pamir and the ∼70 km interface beneath the Tajik Basin are consistent with subduction of the Tajik Basin in this region. We also identify a sub‐Moho interface at a depth of ∼100 km beneath the Tajik Basin. In addition, another shallower interface is identified, where the corresponding pP precursors exhibit polarity opposite to that of pP, indicating a velocity decrease from top to bottom of the interface. These two interfaces likely delineate the upper and lower boundaries of an eastward‐deepening low‐velocity anomaly, which we interpret as the subducted Indian continental crust.