Improving Seismic Velocity Mapping Using Standard Penetration Test Data in a Cokriging Interpolation

In geotechnical studies, a preliminary step is to characterize soil parameters. The objective of this project is to map the velocity of shear sonic waves (Vs) in the soil, while in-depth Vs measurements are limited to a few drillholes. Interpolation based on insufficient measurements results in smoothing the spatial variability of the studied parameter. On the other hand, Standard Penetration Tests (SPT) are abundant in the site under investigation. Being correlated with Vs, the SPT data are used to improve the interpolation of Vs. In the framework of the geostatistics theory, the Vs interpolation is improved using the multivariate method of collocated cokriging. It means the areas lacking Vs measurements are interpolated by the aids of the correlated auxiliary information (SPT); therefore, the spatial variability of Vs is better reproduced. Exploratory data analysis and mapping steps are done entirely in the Isatis.neo™ geostatistical software.