Determination of medium absorption from wide-angle seismic observations with multifold coverage

The paper considers the methods for determining the absorption of seismic oscillations in a two-dimensional inhomogeneous medium by monotype waves detected at correlated profile systems of observations with multifold coverage in a wide range of distances from seismic sources. A new way of transformation of the field of seismic signals (their complex spectral characteristics) is proposed, which is based on the dynamic reciprocity principle and permits one to examine the results of the above observations as a single interrelated set of data appropriate for simultaneous interpretation of the dynamic characteristics of signals coming from a set of sources to a set of detectors. A general equation has been obtained, which Links the amplitude spectra of the transformed seismic signals of reflected, head, and diving waves with the distribution of absorption parameter in a medium. For the multifold observations of diving, reflected, and refracted waves, the means of two-dimensional dynamic tomography of absorption parameter both by each of these waves and by their set in a layered continuous medium are substantiated. The developed methods are intended for a detailed study of the inhomogeneities of a geological medium from the distribution of its dissipative parameters. They may be applied to solving problems on seismic prospecting and investigation of the deep lithosphere zones.