Abstract
<title>Abstract</title> <p> This paper presents a microseismic-based assessment of deformation-related elastic parameters in two structurally different hydraulic facilities: the rockfill dam of the Ohangaron Reservoir and the reinforced-concrete dam of the Andijan Reservoir. The central concept of the study is that the natural vibration characteristics of a dam body, the H/V spectral ratio, compressional and shear wave velocities, and density-derived elastic moduli can be used as non-invasive diagnostic indicators for identifying zones potentially susceptible to deformation under hydrostatic pressure. Ambient microseismic records obtained from field measurements were processed using the H/V spectral ratio technique. For each measurement point, frequency-amplitude relationships, V <sub>P</sub> and V <sub>S</sub> velocities, density, velocity ratio, shear modulus, Lamé parameter, Poisson’s ratio and Young’s modulus were calculated. The results show that the spatial distribution of elastic parameters varies significantly depending on the structural type of the dam. In the rockfill dam, variations in deformation-related parameters are mainly controlled by hydrostatic loading, material density, and the geometrical and lithological heterogeneity of the dam body. In contrast, in the reinforced-concrete dam, these variations are associated with concrete density, acoustic stiffness, and localized stress concentration zones near water-release structures. The findings demonstrate that microseismic methods can be effectively used for evaluating the technical condition of dams, identifying stress-deformation zones caused by hydrostatic pressure, and improving monitoring approaches for hydraulic structures located in seismically active regions. </p>