Seismic surveying to improve the subsurface characteristic interpretations

Abstract

Subsurface exploration determines the characteristics below the earth's surface, such as; stratigraphic sequences and their thicknesses, depth to the bedrock and watertable, etc. The non-destructive methods provide rapid exploration capabilities with minimal consumption of time and financial resources, provided the resultant interpretations are appropriately validated for accuracy. Accordingly, to evaluate the accuracy of seismic surveying, a twelve-channel seismic refraction survey was conducted at the play-ground premises of the University of Moratuwa, and obtained subsurface seismic profiles for the particular location. " Pick Win " and "Plotrefa" software were used to pick the first breaks and plot the time-distance curves respectively to obtain subsurface profiles for each seismic surveying line. The resultant profiles indicated two distinctive layers which resembles a residual soil layer and the completely weathered bedrock. These seismic survey interpretations complement the available resistivity surveying results and borehole information. Additioally , the depth information obtained from seismic slices were used to generate a 3D model through "ESRI ArcMap " and "Surfer" software by rendering depth information to express the contact layer undulations of the residual soil and weathered bedrock. Hence, the study reveals, strength of using multiple geophysical methods to improve the accuracy of subsurface interpretations and modelling capabilities of subsurface layer contacts with a greater accuracy.