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Land subsidence is a global issue and has different causes. Some are natural, like earthquakes , and some are caused by humans. In the United States, land subsidence from over pumping has affected 45 states and accounts for changes in over 17,000 square miles of land which is an area almost 10 times the size of Glacier National Park in Montana ...
The dam monitoring system checks the level of the water because this creates different pressures on the dam, also in relation to the air and water temperature. All these parameters are controlled and compared with the deformation and stress applied on the structure of the dam, measured with extensimeter, pendulum, reverse pendulum, piezometer, etc.
Subsidence frequently causes major problems in karst terrains, where dissolution of limestone by fluid flow in the subsurface creates voids (i.e., caves).If the roof of a void becomes too weak, it can collapse and the overlying rock and earth will fall into the space, causing subsidence at the surface.
where is the tectonically driven subsidence, is the decompacted sediment thickness, is the mean sediment density, is the average depth at which the sedimentary units were deposited, and are the densities of the water and mantle respectively, and the difference in sea-level height between the Present and the time at which the sediments were deposited.
Drivers, processes, and impacts of sinking cities [1]. Sinking cities are urban environments that are in danger of disappearing due to their rapidly changing landscapes.The largest contributors to these cities becoming unlivable are the combined effects of climate change (manifested through sea level rise, intensifying storms, and storm surge), land subsidence, and accelerated urbanization. [2]
These sensors work by sending in small electromagnetic waves into the subsurface level, and receiving information as these waves are returned. [12] Key components of studying land subsidence in the Central Valley include large and small scale monitoring, studying topography in relation to groundwater, and a multi-agency approach.
Indeed, when groundwater usage is not monitored sufficiently, it may result in damage to aquifers or groundwater-related subsidence, as occurred in the Ogallala aquifer in the United States. In some cases, GIS can be used to analyze drainage and groundwater data in order to select suitable sites for groundwater recharge .
Interferometric synthetic aperture radar, abbreviated InSAR (or deprecated IfSAR), is a radar technique used in geodesy and remote sensing.This geodetic method uses two or more synthetic aperture radar (SAR) images to generate maps of surface deformation or digital elevation, using differences in the phase of the waves returning to the satellite [1] [2] [3] or aircraft.