The Use of Seismic Shear Waves and Compressional Waves for Lithological Problems of Shallow Sediments*

Abstract

From a great variety of in situ shear wave experiments, i.e., reflection, refraction and borehole surveys in the shallow sediments of the north German plains, several specific properties have been derived. Shear waves (S) differ from compressional waves (P) in that:1. they are not affected by the degree of water saturation. Thus, they provide a better correlation between the velocity V, and (solid) lithology ; 2. they generally have lower frequencies, but shorter wavelength and, hence, a better resolution of thin layers; 3. they have lower absorption Qs-' and hence a better penetration in partially saturated and gas-containing sediments than P-waves.Correlations have been established between V, and the confining pressure and between reduced V, values and several lithological parameters like the grain size of sandy material.More lithological and hydrological information is obtained by using S-and P-wave surveys along the same profile. The best information on a sedimentological structure is obtained by the simultaneous observation of V,, V,, Q, and Q, .

Estimation of near-surface geotechnical parameters using seismic measurements at the proposed KACST expansion site, Riyadh, KSA

“…It is unconsolidated material of the earth's crust used to build upon or used as a construction material. The seismic method has emerged as a powerful tool in computing the elastic moduli from which their elastic deformation can be estimated (Stumpel et al 1984;Davis and Taylor 1979). The technique has been successfully applied for mapping depth to the base of backfilled quarries, depth of landfills, thickness of overburden, and the topography of groundwater aquifers.…”

Seismic Investigation in the Bertioga Coastal Plain, Brazil

“…The order of magnitude observed is consistent with those found in the literature for similar sediments. Stuempel et al (1984), having compiled results from seismic tests of refraction, reflection and drilling holes obtained in saturated shallow sediments in the Northern Germany, report high values for the Vp/Vs ratio, even for those partially saturated, and extremely high values for clayey horizons.…”

Italian accelerometric archive: geological, geophysical and geotechnical investigations at strong-motion stations

“…In the project the seismic refraction technique is applied generating both compressional and horizontally polarized shear waves (SH). The use of SH waves is preferable as they do not convert in other wave types in correspondence of horizontal interfaces between soils with different seismic rigidity, decreasing the uncertainties of other seismic techniques (Mc Cornack et al 1984;Stümpel et al 1984;Milkereit et al 1986;Gasperini et al 1994;Blair and Korringa 1987). The occurrence in the seismograms of converted waves generated by not horizontal interfaces (Xia et al 2002), has been prevented by using the cross-over acquisition procedure (Rainone et al 2009).…”

“…9b) and, for each channel, an array of five horizontal geophones was used to obtain analogue filtering for surface waves (Stümpel et al 1984). An off-end spread was used, employing a shot and geophonic group spacing of 2 m and an offset of 6 m. The choice of having a small geophone spacing is justified by the need of having a high number of Common Depth Point (CDP) for length unit (Knapp and Steeples 1986), considering the heterogeneity of the geological deposits.…”