Аннотация:The purpose of the work is to establish the peculiarities of ground vibrations in the near-field zone. The fact is that the existing ideas about generation and propagation of seismic waves in this zone poorly agree with empirical data. The ground vibrations in this zone during explosions and earthquakes are compared. A method of plotting the level of the day surface as a function of time after the moment of explosion is proposed. As a result of ground motion analysis, it is concluded that stresses in rocks during explosion are released in the form of damped standing waves. The amplitude of such oscillations far exceeds the level of generated volumetric seismic waves. And since the mass of oscillating rocks is much greater than the mass of the near-surface layer of ground, the latter have practically no effect on the spectrum and duration of oscillations. Similar processes in earthquakes differ only in the fact that the stresses in rocks exist before the beginning of movement along the fault. The verification showed that in contrast to the ideas about wave generation and propagation used in normative documents of earthquake-resistant construction, the parameters of vibrations in the near-fault zone do not depend on ground conditions. This fact is noted by many researchers. Consequently, many provisions of building codes should be revised. For example, the ground models used in NERA, STRATA, etc. programs are based on the assumption of passing waves and therefore the use of these programs is inappropriate.
