Geophysical surveys in the Kashmir valley (J&K Himalayas) part I: Estimation of dynamic parameters for soils and investigation of the deep basin structure

Abstract

A combined set of multichannel analysis of surface waves (MASW) and single-station microtremor horizontal-to-vertical spectral ratio (MHVSR) testing was performed at over 190 sites within the complete Kashmir Basin, mainly concentrated within the Greater Srinagar region. The aim was to establish the dynamic parameters of the main geomorphological units, especially the sedimentary deposits (Alluvial and Karewa) in the valley through widespread geophysical testing. Shear wave velocity (VS) and frequency parameters were estimated for each of the sites. Multiple impedance contrasts in the HVSR curves were found within the sedimentary deposits indicating a number of stratigraphic layers which were then correlated with the geology of the region. Further, forward modelling routine was utilised to extend the VS profile to deeper depths, to determine the first-order estimate bedrock depth and establish the basin structure which remains largely unexplored till now. Lastly, geological cross-sections were constructed using these results from the geophysical tests. © 2023 Elsevier Ltd