Problems of Engineering Seismology: article

Аnnotation: In this paper, the system of seismic microzonation (SMZ) is presented in the form of a seismic channel, one of the most important characteristics of which is the dynamic range. The value of the dynamic range D is usually expressed in logarithmic measure in terms of units called decibels. The introduction of decibels due to their dimensionless nature is a universal means of assessing the quality of work of both the seismic channel as a whole and its individual links. The use of this characteristic makes it possible to correctly assess the contribution of various factors of the geological situation (seismic rigidity, waterlogged soils, relief, spectral features, nonlinearity, etc.) to the total value of seismic intensity. The assessment of the contributions of various components of the seismic intensity increment yielded the following results: seismic rigidity increases the seismic impact by 6 dB; taking into account waterlogging does not require an additional correction; the influence of resonant phenomena is estimated at about 10.5 dB; the influence of relief – no more than 3.5 dB. It is proposed to combine the influence of resonance and antiresonance on the change in the increment of seismic intensity, designating all this influence by the term “structural factor”. Non-linearity reduces the dynamic range of influence of both various factors and its overall value. Finding out the causes of ultra-high values of seismic intensity due to local conditions requires further development. The obtained estimates are intended to enhance the effectiveness of the SMZ methodology.