SEG Summer Field Camp: Multigeophysical imaging of an aquifer in the Astara region of Azerbaijan

Groundwater faces growing pressure due to human activities and the impacts of global climate change. Therefore, it is imperative to characterize near-surface aquifers, especially those that are unconfined because they are particularly vulnerable to these challenges. In Azerbaijan, alluvial plain aquifers represent a critical facet of the nation's water resources, yet they remain largely understudied. The objective of our study is to employ a multigeophysical survey (including electrical resistivity, seismic refraction, and ground-penetrating radar) to describe the subsurface attributes of an unconfined alluvial aquifer situated within an agricultural field in Astara, Azerbaijan. These data were acquired during the 2023 SEG Summer Field Camp by global students and specialists. Based on our general knowledge of the area, we interpret our findings as a subsurface with four distinct layers. The first is an initial 1 m thick soil layer covering the second layer, which is a more permeable unconfined aquifer likely consisting of a mixture of sand, pebbles, and gravel with a silty matrix (3 m thick). The third is a potential confining layer that is possibly clayey. The fourth layer is a presumed confined aquifer at a depth of 10 m. These results shed light on previously unstudied alluvial plain aquifers and contribute to comprehension of the hydrogeologic conditions at the local scale. To provide a broader understanding at the regional scale, the survey area should be extended and linked to borehole data to improve the interpretation of the geophysical results.