Exploring Liquefaction Susceptibility of Northern Gulf of Kutch Region in Gujarat Through MASW Analysis: A Case Study

Soil liquefaction is critical for the very loose soil deposit in the earthquake-prone area. A detailed site investigation and liquefaction analysis are necessary to construct massive structures (such as oil tanks and high-rise skyscrapers) in these soil conditions. The multichannel analysis of surface waves (MASW) technique is a non-invasive and quick test to estimate the shear wave velocity (Vs) profile. This work presents a case study of liquefaction analysis and soil site classification of the Northern Gulf of Kutch region in the state of Gujarat, India, using the MASW technique. Geophone spacing of 1.5 m with an offset distance of 15 m was used for the data acquisition. The source was activated by hammering to generate wavefields. The wavefields were recorded at the sampling frequency of 4000 Hz for a duration of 0.6 s at nine locations. The phase shift method was used for the dispersion analysis of these wavefields, and teaching–learning based optimization was used for the inversion analysis to estimate the Vs profile. The Northern Gulf of the Kutch region was categorized as site class D (stiff soil) based on the National Earthquake Hazard Reduction Programme (NEHRP), and the predicted Vs30 values from all sites ranged from 180 to 360 m/s. The liquefaction analysis based on Vs values suggested that there was a risk of liquefaction because of loose soil layers in the top 12 m.