Contribution of geophysical methods for detecting underground cavities in the Abda-Doukkala region (Morocco)

The present paper examines the contribution of geophysical methods to the detection of underground cavities, with a particular focus on a case study in the Sahel region between El Jadida and Safi. This coastal area, marked by urban development and critical infrastructure, faces significant risks due to cavity formation and potential subsidence, which pose threats to local populations and essential transport networks. To address these challenges, the study employs an integrated geophysical approach, combining Electrical Resistivity Tomography (ERT), Ground-Penetrating Radar (GPR), and borehole drilling. Each method plays a distinct yet complementary role in cavity detection. ERT identifies resistivity anomalies associated with subsurface voids, offering insight into deeper structures. GPR provides high-resolution imaging of shallow subsurface features, allowing for the identification of cavities near the surface. Borehole drilling serves as a direct validation tool, confirming anomalies detected by ERT and GPR. The integration of these methods enhances the precision, reliability, and depth of cavity detection, enabling accurate mapping and characterization of underground anomalies. This methodological synergy facilitates risk assessment and early intervention, offering a robust framework for monitoring subsidence-prone areas and supporting decision-makers in the implementation of preventative measures. By safeguarding infrastructure and local communities from potential collapses, this study highlights the importance of geophysical techniques in mitigating geotechnical hazards. The results underscore the vital role of geophysics in enhancing safety, infrastructure resilience, and sustainable urban development in vulnerable coastal regions, demonstrating the effectiveness of multidisciplinary approaches to addressing complex subsurface challenges. This approach promotes proactive risk management, reducing potential socio-economic impacts and ensuring long-term infrastructure sustainability.