The results of experiments on simultaneous recording of seismic signals from various sources on the Earth surface and at a depth of up to 250 m are stated. The peculiarities of change with depth of the spectral composition of teleseismic earthquake and microseismic oscillations have been studied, which testify in favour of a significant decrease in the level of seismic effects on underground structures in a wide range of frequencies in relation to buildings and structures on the daylight surface. [ABSTRACT FROM AUTHOR]