Near-surface VSP surveys using the seismic cone penetrometer

We have found that high-quality vertical seismic profile (VSP) data can be collected for near-surface applications using the seismic cone penetrometer. Cone-mounted accelerometers are used as the VSP receivers, and a sledgehammer against the cone truck baseplate is used as a source. This technique eliminates the need to drill a borehole, thereby reducing the cost of the survey, and results in a less invasive means of obtaining VSP data. Two SH-wave VSP surveys were acquired over a deltaic sand/silt sequence and compared to an SH-wave common-depth-point (CDP) reflection profile. The VSP data were processed using a combination of singular-value-decomposition filtering, deconvolution, and f-k filtering to produce the final VSP extracted traces. The VSP traces correlate well with cone geotechnical logs and the CDP surface-seismic data. The first breaks from the VSP can be used to generate shear-wave velocity profiles that are important for time-to-depth conversion and the velocity correction of the CDP surface data.