Evaluation of seismic properties of water-saturated soils for solving problems in seismic microzoning

The experts involved in seismic microzoning (SMZ) have different opinions on whether to take into account the response of water-saturated fine soils upon the assessment of expected seismic effect. When using the method of seismic stiffness (MSS), a number of researchers consider inexpedient to apply the correction for the groundwater level (GWL). In the present paper, we analyze both the results of our own field studies and those of other researchers involved in the development of SMZ methodology. Particular attention is paid to the GWL influence on the increment of seismic intensity (ΔIGWL ) in the S.V. Medvedev’s equation upon MSS calculations by transverse s-waves. The research results provided in this paper prove that the correction for ΔIGWL should not be ignored in calculations of the seismic intensity increment. The authors appear it expedient to continue field tests in the registration of strong movements in water-saturated fine soils.