Editorial for Special Issue “Monitoring Land Subsidence Using Remote Sensing”

Land subsidence is a geological hazard that affects several different communities around the world. The main consequences of subsidence can be related to environmental degradation, damage to buildings, and interruption of services. The effects produced by the lowering of the ground level on building and infrastructure can be considered as a major problem in many countries. More than 150 cities all over the world have endured land subsidence with rates up to tens of centimeters per year. Land subsidence can have both natural and anthropogenic origin: natural subsidence can be due to the compaction of lithological layers of the soil, the oxidation of peat, and geodynamic processes (e.g., tectonic-plate movements, volcanism); anthropogenic subsidence derives mainly from the compaction of aquifers associated with groundwater/oil/natural gas extractions, drainage of organic soils, underground mining, hydrocompaction, sinkholes, stress provided by newly-built man-made structures, and thawing permafrost; the combination and coexistence of these factors have a strong negative impact on the territory. The effects of this global problem are more evident along transitional environments, such as coastal areas, deltas, wetlands, and lagoons, which are becoming increasingly vulnerable to flooding, storm surges, salinization, and permanent inundation. In these areas, the effects of subsidence are linked also to the retreat of coastlines and disappearance of emerged surfaces.