Treatise on geophysics. Deep Earth seismology. An introduction and overview / Трактат по геофизике. Глубинная сейсмология Земли. Введение и обзор

Applications of seismology to the study of the Earth’s interior are only a little over 100 years old. Its tools in determining the properties of inaccessible Earth are the most powerful among all geophysical methods. The principal reasons are the availability of natural (earthquakes) or controlled (explosions and vibrators) sources of elastic waves and their relatively low attenuation with distance. Seismological methods span some six orders of magnitude in frequency, and the depth of an investigated structure may range from a few meters in engineering applications to the center of the Earth. Progress in seismology has been achieved through developments on several fronts: theory, instrumentation, and its deployment, as well as computational resources.
Even though the studies of earthquakes and the Earth’s structure are closely related, the two subjects are often discussed separately. This volume is devoted to the Earth’s structure and Volume 4 to studies of earthquakes. Nevertheless, the relationship is intimate. For example, it is possible to formulate an inverse problem in which earthquake locations are sought simultaneously with the parameters of the Earth’s structure, including three-dimensional (3-D) models (see Chapter 1.10).  <...>