Accession Number : ADA189709

Title :   Military Hydrology. Report 15. The Seismic Refraction Compression-Shear Wave Velocity Ratio as an Indicator of Shallow Water Tables: A Field Test,

Corporate Author : ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS ENVIRONMENTAL LAB

Personal Author(s) : Schuyler-Rossie, Christine

PDF Url : ADA189709

Report Date : Nov 1987

Pagination or Media Count : 48

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.

Descriptors :   *SEISMIC DETECTION, *SEISMIC WAVES, *WATER TABLE, ALLUVIUM, BURIED OBJECTS, CYLINDRICAL BODIES, FIELD TESTS, GEOPHYSICS, GROUND WATER, HYDROLOGY, MILITARY ENGINEERING, MODELS, RANGE(DISTANCE), RATIOS, RECEIVERS, REFRACTION, RELIABILITY, SECONDARY WAVES, SEDIMENTS, SHALLOW DEPTH, SHEAR PROPERTIES, STEEL, SURVEYS, THEORY, VELOCITY, PRIMARY WAVES(SEISMIC WAVES)

Subject Categories : Seismic Detection and Detectors
      Hydrology, Limnology and Potamology

Distribution Statement : APPROVED FOR PUBLIC RELEASE