Intermediate-depth earthquakes beneath the Pamir Hindu Kush Region: Evidence for collision between two opposite subduction zones

We employed a double-difference algorithm (hypoDD) to relocate earthquakes within the region bounded by 66°E-78°E and 32°N-42°N in the period of 1964-2003 reported by the International Seismological Center (ISC). The improved hypocentral locations delineate a double-layered Wadati-Benioff zone in the eastern Hindu Kush intermediate seismic belt. Based on this feature and other evidences, we propose that the intermediate-depth earthquakes beneath the Pamir-Hindu Kush region may occur in two collided subduction zones with opposite dip directions.