Military Hydrology. Report 15. The Seismic Refraction Compression-Shear Wave Velocity Ratio as an Indicator of Shallow Water Tables: A Field Test,
Abstract
To test the assumption that the velocity of shear waves increases much less than the velocity of compressional waves at a water table, a seismic refraction survey was performed over a shallow water in alluvial sediment. Using a sledge hammer and a partially buried steel cylinder as a source, a maximum shot to receiver distance of 330 ft and depth of investigation of 60 ft were achieved. The ratio of Vp to Vs (compressional/shear wave velocity) at the water table was found to be 2.48. In the four nonsaturated layers above the water table, Vp/Vs ratios ranged from 1.54 to 1.55. As predicted by the theoretical models considered, shear wave velocity did not increase measurably at the water table. In an area in which a shallow water table was not likely to exist, shear wave velocity increased by a least as much as the increase in compressional velocity at each refractor. Results indicate that the comparison of S- and P-wave velocity profiles is a promising technique for water table detection. However, more research is necessary to define the reliability and limits of the method. Keywords: Compression, Geophysics, Ground water, Military hydrology, Seismic refraction, Shear wave velocity, Wave velocity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1987
- Accession Number
- ADA189709
Entities
People
- Christine Schuyler-rossie