Using active and passive remote sensing techniques to quantify the surface deformation and lithology of salt diapirs, Zagros Mountains, southern Iran

Salt diapirs and their caprocks are strategically significant for natural resource exploration and as potential sites for nuclear waste and CO₂ storage. However, direct study of these systems is challenging because most diapirs are not exposed at the Earth’s surface. The Zagros Mountains in Iran, with their numerous exposed salt diapirs and caprocks, provide a rare and valuable opportunity to investigate the dynamics of active diapir-caprock systems.

In this study, we combine traditional fieldwork, space-based geodetic mapping, remote spectral analysis, and petrology to analyze the active processes and driving forces that shape salt diapir surfaces within the interconnected climate-diapir-caprock system.

The quantification of surface deformation of salt diapirs and their composition is challenging to map in field campaigns due to their rough terrain and remote location in the Zagros Mountains, southern Iran. To better understand patterns of the salt diapir’s surface deformation and composition active and passive remote sensing techniques are essential. However, the contemporary vertical surface deformation pattern is difficult to detect and interpret along disciplinary boundaries. With the aid of high-resolution PSI measurements and multispectral imagery analysis we detected high-precision spatiotemporal deformation patterns of the surfaces of several salt diapirs. In addition, time-series analysis helped to distinguish between salt-supply-driven domal uplift and vertical surface modification induced by precipitation, dissolution, and erosion.

We analysed Sentinel-1 PSI time-series, processed by the German Aerospace Center (DLR), to obtain the highest available spatiotemporal resolution of the vertical surface-deformation pattern across three diapirs – Karmostaj, Siah Taq, and Champeh – in the Zagros Mountains. We then correlated the Persistent Scatterers to the respective diapir’s composition based on multispectral analysis of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite images. Preliminary results indicate that the deformation pattern of the salt diapirs does not correlate with seasonal effects, such as precipitation and heat. The vertical surface deformation pattern on these three diapirs implies that these diapirs are active. We conclude that the strategic integration of space-based geodesy and remote spectral analysis provides an effective method for interpreting the complex surface deformation patterns of salt diapirs. The activity of salt diapirs should be considered a key factor in resource exploration, as well as in the evaluation of sites for nuclear waste and CO₂ storage.