| Abstrakt: |
In the present study, we investigate the subsidence phenomenon affecting some neighborhoods located to the west of the city of Maceió, State of Alagoas (northeastern Brazil), which is due to the underground solution mining of halite (NaCl) from 1977 to 2019. The first symptoms of this phenomenon, such as surface cracks, ground depressions, small earthquakes, etc., began to be noticed only in 2018. So far, it has already caused enormous damage to the local population, resulting in the creation of true "ghost" neighborhoods. In this study, we have integrated surface displacement determined from satellite images using the persistent scatterer interferometry and the small baseline subset (SBAS) InSAR techniques for the period of 2016–2020, and 2D numerical modelling based on the finite element method. The results showed a wide surface subsidence (2.6 km2) with maximum vertical displacements of − 100 cm and maximum subsidence rate of − 22 cm/year. Variations in the mechanical properties of geological faults significantly affect surface subsidence pattern. We speculate that the reactivation of fractures may be an important mechanism leading to the formation/propagation of numerous cracks at the surface. Finally, the study may provide a better understanding about settlement dynamics in salt dissolution fields. [ABSTRACT FROM AUTHOR] |
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