Initially developed for use in the oil industry, Seismic Surveying, and its myriad of techniques (such as Seismic Refraction and MASW), is now considered a valuable tool for non-destructively assessing the structure and competence of subsurface soils and rock.
Seismic surveying is particularly beneficial when used for the following purposes:
- Mapping of soil thickness overlying bedrock along linear routes such as road corridors, new cable routes and pipelines.
- Determining soil and rock in-situ stiffness characteristics via the calculation of moduli of elasticity.
- Mapping subsurface rock quality using compressional "p" wave velocity analysis to yield rock rip ability
- Mapping subsurface soil and rock strength using shear "s" wave velocity analysis. The resulting data can be converted to provide a 2D profile (like that below) represented as Standard Penetration test "N" values
- In marine environments seismic reflection is used to profile sub seabed sediments to identify layer boundaries and aid identification of sediment types. (E.g. Sub surface "Boomer" and "Pinger" surveys / CHIRP surveys)
- Extrapolating rock and soil interfaces between exploratory holes
- Providing preliminary information with respect to rip ability along new cable and pipeline routes.
- Provision of accurate soil and rock stiffness data typical for a site and not reliant on recovery of intact rock cores or expensive Geobore "S" soil cores