Geophysical Techniques for Reconnaissance Investigations of Soils and Surficial Deposits in Mountainous Terrain1
- C. G. Olson and
- J. A. Doolittle2
Two geophysical techniques—ground-penetrating radar (GPR) and seismic refraction—were assessed for their capabilities in reconnaissance studies of soil characteristics, depth to the water table, and depth to bedrock beneath surficial deposits in mountainous terrain. Ground-penetrating radar had the best near-surface resolution in the upper 2 m of the profile and provided continuous interpretable imagery of soil profiles and bedrock surfaces. Where thick colluvium blankets side slopes, the GPR could not consistently define the bedrock interface. In areas with clayey or shaley sediments, the GPR is also more limited in defining depth and is less reliable. Seismic refraction proved useful in determining the elevation of the water table and depth to bedrock, regardless of thickness of overlying material, but could not distinguish soil-profile characteristics. Although both techniques provide adequate information for reconnaissance purposes, these techniques have a greater probability of success in areas where there is some subsurface information. Independent use of any one method is advised only where ground control is well documented.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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