Geochemistry is most obviously defined as the "study of the chemistry of the Earth." In the broadest sense, the subject attempts to describe and understand the distribution of the elements (and their isotopes) in all parts of the Earth; the atmosphere, and hydrosphere, the Earth's crust, and its deeper interior (mantle and core). However, geochemists have traditionally concentrated their attention on the solid Earth and on surface or near-surface processes involving fluids, leaving the atmosphere and hydrosphere to other specialists such as the atmospheric scientists and chemical oceanographers. Geochemists have also concerned themselves with the chemistry of extraterrestrial matter (strictly termed cosmochemistry) because of its importance in understanding the origin and history of the solar system and hence of the Earth. A recent, and very welcome, development is the growth of interdisciplinary fields (such as biogeochemistry) and a return to attempts to view the chemical systems of the Earth (lithosphere, hydrosphere, biosphere, and atmosphere) as a whole. <...>

After every major earthquake, the Earth rings like a large bell for several days. These free oscillations of the Earth are routinely detected at modern broad-band seismographic stations, which are now distributed globally. The eigenfrequencies and decay rates of the vibrations can be measured and used to constrain the radial and lateral distribution of density, seismic wave speed and anelastic attenuation within the interior.

This book outlines the scientific, methodological, and practical foundations for the application of the HRS-Geo technology, the purpose of which is to build detailed 2D and 3D seismoacoustic models in the form of effective acoustic impedance (AI), reflection coefficients (RC), and the most important geological indicators for prospecting and industrial exploration of real geological environment. Particular attention is paid to improving the process of searching for the AI and RC model using the vector of objective functions, for which various types of residuals between real and model data are iteratively calculated. Such residuals are estimated from he energy (amplitudes) and the shape of the seismic signal.

The maturing of the Earth sciences has led to a fragmentation into subdisciplines which speak imperfectly to one another. Some of these subdisciplines are field geology, petrology, mineralogy, geochemistry, geodesy and seismology, and these in turn are split into even finer units. The science has also expanded to include the planets and even the cosmos. The practitioners in each of these fields tend to view the Earth in a completely different way. Discoveries in one field diffuse only slowly into the consciousness of a specialist in another. In spite of the fact that there is only one Earth, there are probably more Theories of the Earth than there are of astronomy, particle physics or cell biology where there arc uncountable samples of each object. Even where there is cross-talk among disciplines, it is usually as noisy as static. Too often, one discipline’s unproven assumptions or dogmas are treated as firm boundary conditions for a theoretician in a slightly overlapping area. The data of each subdiscipline are usually consistent with a range of hypotheses. The possibilities can be narrowed considerably as more and more diverse data are brought to bear on a particular problem.