In this paper, a technique for estimating diverse physical properties of bottom deposits is discussed. The methodology is based on the evaluation of reflection coefficients of stratigraphic boundaries using the amplitudes of bottom and multiple acoustic reflectors by the so-called quotient method in combination with the regression equations of Hamilton. For practical application of this technique, the determination of the reflection coefficient and its accuracy in the case of non-vertical incident acoustic waves are considered. By means of theoretical modeling of seismic traces, the relationship between average sediment properties and estimated values was investigated for thin layered media. It is shown that the average thickness is defined by 1/4 of the length of the first main phase of the acoustic signal in the time domain.
The described technique was applied on two seismic profiles with distinct characteristics: a low-frequency multi-channel airgun-array profile and a high-frequency single-channel sparker profile, both acquired in the Southern Basin of Lake Baikal, Siberia. The results obtained using the low-frequency data suggest the presence of an average 4.8 m thick sand-silt-clay layer, while the high-frequency data detail the upper 40 cm layer of the lake bed deposits of Lake Baikal as a silt-clay one. These conclusions are in good agreement with the deep water drilling results in the region.
The estimation of various physical properties of bottom sediments in seas and deep lakes, and subsequent sorting of bottom areas based on these data, are important for regional research of water basins, for solution of tasks of engineering geophysics and geotechnical problems and for geological research of sediments by means of core sampling.