Measuring land subsidence: techniques and applications
Land subsidence is caused by both natural (e.g., tectonics, Glacial Isostatic Adjustment -GIA) and anthropogenic-induced (e.g., fluid extraction) processes and occurs at a variety of temporal and spatial scales. Thus, when designing subsidence measurements, it is important to account for the expected temporal and spatial scales of each studied subsidence case. For example, measurements of a regional scale GIA-induced subsidence (hundreds of kilometers) require different measurement techniques than of a localized sinkhole-induced subsidence (tens of meters). Space geodetic techniques, in particular GNSS and InSAR, provide a wide range of measurement scales that can monitor many subsidence types. In this presentation, I will cover the main subsidence measurement techniques, the advantages and limitation of each technique, methods for overcoming the limitations, and the significance of the measurements. Each of presented topics will be explained using case studies.