QUASI-STATIONARY FORM OF THE SPECTRUM OF INTENSE SEISMIC WAVES AT THE SURFACE OF THE GROUND

Abstract

Transformations of spectra of intense seismic waves propagating in ground columns are studied in numerical experiments. It was found that transformation of spectra to the form E( f ) ~ f –k in the ground occurs due to nonlinear (hysteresis) energy dissipation and redistribution of the energy of oscillations in the spectrum by means of interaction between waves. Emphasizing the low-frequency components agrees with the Manley–Row relations of decay instability, according to which energy transport of low-frequency oscillations to high-frequency oscillations is hampered, but decay of high-frequency oscillations and transport of their energy to low-frequency oscillations is facilitated.