INTEGRATED UAV, GNSS AND GPR METHODS FOR KARST TERRAIN ANALYSIS IN AN ARID REGION: A CASE STUDY FROM THE SAURA VALLEY, WESTERN KAZAKHSTAN

Abstract

Karst processes have a significant impact on the formation of the relief in the Mangystau region (Western Kazakhstan), where arid climatic conditions and the predominance of carbonate rocks contribute to the development of both surface and subsurface karst forms. The aim of this study is the identification of potential geohazards in the Saura Valley (Mangystau region) through an integrated surface and subsurface investigation method. The meth odological framework combines high-resolution photogrammetry using an unmanned aerial vehicle (UAV), GNSS georeferencing, and low-frequency ground-penetrating radar profiling. UAV surveys with the Autel EVO II RTK Pro (V3) produced orthophotomaps and a digital elevation model (DEM), which formed the basis for detailed morphometric analysis. Subsurface investigations using the GPR Zond Aero LF identified three distinct loosening zones that coincided with structural faults. GNSS measurements with the SOUTH Galaxy G9 receiver ensured centimeter-level spatial accuracy across all datasets. The collected data were integrated and analyzed within a GIS environment to establish spatial correlations between surface morphology, geophysical anomalies, and tectonic structures. The results confirm the structurally controlled nature of karst development and demonstrate the effectiveness of an integrated approach for detecting potentially unstable karst zones in ari d environments. Geotourism represents a promising direction for the rational use of karst terrains, offering scientific, aesthetic, and recreational benefits. However, the environmental vulnerability of karst terrains requires a balanced approach to tourism development, incorporating long-term monitoring and planning to preserve their natural integrity.