Article,
The use of seismic shear waves and compressional waves for lithological problems of shallow sediments
Geophysical Prospecting, 32 (4): 662--675 (August 1984)
DOI: 10.1111/j.1365-2478.1984.tb01712.x
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 Vs 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-1 and hence a better penetration in partially saturated
and gas-containing sediments than P-waves. Correlations have been
established between Vs and the confining pressure and between reduced
Vs 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 Vs, Vp, Qs and Qp.
