## 2 Previous Studies
Using the 434 boreholes in this study, the main soil types in the city of Kolkata were found to be clay, silt, and silty sand. [PERSON] et al. [3] investigated the SPT and shear wave velocity of soil in several coastal cities on the Caspian Sea. In this study, downhole tests were performed to calculate the shear wave velocity profile in all the study sites using the same borehole and, in some cases, drilling a new borehole. After that, the data were analyzed, to determine the correlation via a suitable statistical method. The results indicated that the obtained relationship is suitably compatible with the universal practical relationship presented for sandy soils, and is approximately at the upper limit of the relationship. A new empirical formula that can be used to correlate the SPT-N and V\({}_{\text{s}}\) values for the typical soil materials encountered in north Florida was suggested by [PERSON] et al. [4]. Soil classification information, the shear wave velocity (derived via the MASWs method), and SPT-N values were gathered from four geotechnical and geophysical investigations conducted in this region. Through the employment of the M5 model tree algorithm, the relationship between the V\({}_{\text{s}}\) and SPT-N values was predicted using the collected dataset. The accuracy of the new proposed equation was determined through the measurement of the correlation coefficient. The proposed correlation was also compared with previously suggested formulas for V\({}_{\text{s}}\) determination through the measurement of the root-mean-square error of each formula. [PERSON] et al. [5] examined the development of a reliable correlation between Vs, measured via a multi-channel analysis of surface wave tests, and N, measured via SPT at various sites in the Roorkee region. These tests were carried out at ten different sites in Roorkee (within a radius of 30 km). Additionally, based on statistical assessments, an empirical correlation between V\({}_{\text{s}}\) and N was developed for all types of soils, sand, and clay. Empirical equations for the Vs and SPT-N values in different soil types in different regions of the world were examined by [PERSON] and [PERSON] [6]. These equations were selected separately, and statistical regression analyses were carried out to develop new common correlations for each type of soil. The newly developed equations had best-fit curves with very high R\({}^{2}\) values, along with minimum variance. [PERSON] et al. [7] investigated the correlation between the shear wave velocity and standard penetration test blow counts in all soil types, gravelly soil, sandy soil, and clayey soil for the city of Mashhad in the northeastern region of Iran. The V\({}_{\text{S}}\) data used were measured via the downhole method in 88 boreholes. The obtained results showed that the \(N\)-value played a critical role in the estimation of V\({}_{\text{S}}\), and the soil type was less effective in this regard. There was a relative similarity between the regression equations obtained in this study and those previously published. [PERSON] and [PERSON] [8] investigated generalized correlations between the shear wave velocity and SPT-N values for all soil types at a generalized depth, using the concept of regression. Soil profiles taken as input for analysis were collected from 245 boreholes in the Madhya Pradesh region (India). The researchers stated that multiple linear perceptron and generalized regression neural network models using MATLAB coding gave better results than linear regression analysis, when applied to site-specific ground response analysis.