DETERMINATION OF SUBSURFACE VELOCITY USING MULTICHANNEL ANALYSIS OF SURFACE WAVES

Abstract

The estimation of the in-situ shear wave velocity is carried out using various geophysical and other engineering techniques and methods. In this project, Multichannel analysis of the subsurface waves has been used. The most extensively used technique by geophysicists and geotechnical engineers is Multichannel Analysis of Surface Wave (MASW). The major reason behind the widespread use of this particular method is being its simplicity in generating and propagating the surface wave energy, and also the use of MASW method reduces cultural noise, improves the ground surface conditions. The study area mainly falls in the lesser Himalayan terrain constitutes well defined low linear ranges of Siwalik sediments and rocks of Frontal Fold belt and is characterized by strike ridges, dip slopes with steep obsequent scarps, rectangular to trellis drainage pattern controlled by bedding and joints. The data acquisition for the multichannel analysis of surface waves has been carried out using the TROMINO. Grilla software has been used to analyze the obtained results. There are two sites where the study has been done and the results obtained at site1: Donal Khad, a total of 3 distinct interval velocities for respective depths can be identified and are present up to depth of 30 m. The value for the Vs(0.0-30) = 448 m/s and for the site2: Balaknath Temple also 3 distinct interval velocities for respective depths can be identified and are present up to depth of 30 m. The value for the Vs(0.0-30) = 495 m/s .