Abstract
Hydrotechnical structures, being vital infrastructural objects, at the same time represent a great danger for human activity and the environment. The article discusses the results of geophysical studies of an earth dam in Kazakhstan. Despite its key role in agricultural water supply, the loam dam has not previously been subjected to a thorough geophysical evaluation. The study combines seismic refraction tomography using the correlation method of refracted waves with self-potential measurements to non-invasively detect internal heterogeneities and potential seepage pathways. Over one kilometre of seismic profiling has been performed with both P- and S-wave registrations by using standard geophones and pulse sources, allowing imaging to depths of up to 40 meters. Data processing included noise reduction, first arrival sampling, and velocity modelling with vertical gradients. The results show significant lithological and structural variability in the dam body. Subsidence anomalies with increasing permeable loams and low velocity zones have been identified, and soil loosening has been detected, indicating a possible seepage site. The comparison of seismic data and self-potential measurements has showed the highest correlation near the dam crest, with partial overlap elsewhere due to soil heterogeneity, metal structures, moisture changes, and complex topography. The combined interpretation has allowed identifying the main seepage zones in the dam body. The results of the study confirm the effectiveness of combining the correlation method of refracted waves and the self-potential method for detailed diagnostics of earth dams. The integrated approach allows for depth-resolved characterization and the development of a seepage regime model that identifies critical risk zones. Further detailed permeability testing, real-time seepage monitoring, and regular geophysical and hydrogeological surveys are recommended, especially near residential areas. The results of the surveys provide a solid foundation for engineering measures to enhance dam safety and mitigate the risk of failure. As part of the Geographic Information System platform, the data obtained are useful for monitoring the condition of dams, assessing their risks and impact on the environment, and for effective water resource management.