Subduction of continental crust beneath Hindu Kush to ∼180 km depth. Highest seismic strain rates and largest earthquakes deeper than 180 km. Break-off develops along-strike of seismic zone at base of subducted continental crust. Intermediate-depth seismicity in the upper part (60–180 km) in crustal rocks. Seismicity in the deeper part (180–265 km) due to deformation in mantle lithosphere.