Structure of the Kashmir Himalaya from Deep Seismic Soundings

Deep Seismic Sounding (DSS) studies carried out for the first time in the syntaxial bend of the Himalaya in Kashmir region during 1974 and 1975 have revealed the deep crustal and upper mantle structure in the region of the great Himalaya Karakorum-Pamir ranges. The Moho which is at a depth of about 45 km near Sopur changes rapidly to 54 km depth in the region of Wular lake from where it continues to go still deeper towards NNE, attaining a depth of about 64 km near Kanzalwan. Then there is a deep fault displacing Moho to a depth of 76 km, which then rises to about 62 km under the Nangaparbat shot point. Similarly the Moho, along profile 2, is found to be at a depth of about 53 km in the region about 10 km NNW of Tral going still deeper towards NNW and attaining a depth of about 64 km in the region about 17km NE of Srinagar. Further NNW, in the region of Kanzalwan, there seems to be some flattening of the Moho boundary which is at a depth of about 70km. Beyond Kanzalwan both the profiles 1 and 2, reveal a change in the dip direction on the Moho boundary which then starts rising up towards Nangaparbat. This updip of the Moho boundary in the region between Kanzalwan and Nangaparbat is an indication of the upwarp of the Moho in this region, which could be responsible for the uplift of the Nangaparbat massif. The crustal block in the Kashmir Himalayan region between Sopur and Kanzalwan and between Tral and Kanzalwan appears to be bounded by two large-angle deep-faults which extend down almost to the Moho boundary.

A number of deep reflections have been recorded along profile 3 indicating deep reflecting boundary at a depth of about 140km extending right from beneath Nangaparbat to the great Pamir ranges which is inferred as representing the top of the asthenospheric layer.