Monitoring Land Subsidence using Persistent Scatterer Interferometry Time Series Analysis and Groundwater Level Variations: (Case Study: Sarab Plain)

Land subsidence is nowadays a usual phenomenon in the world. It can cause significant damages to transportation networks, facilities and structures. This study aims to monitor land subsidence in Sarab plain and its relation with groundwater level variations. Sarab Plain is one of the plains in East Azerbaijan province with high vulnerability to land subsidence. However, no study has been reported in the plain on investigating the relationship between groundwater level variations and land subsidence based on velocity maps. In this paper, in order to increase the accuracy of determining land subsidence, Persistent Scatterer time series analysis is applied using 36 Sentinel-1A datasets from 2017 to 2020. The maximum subsidence rate of about -45 mm/year in the vertical direction was obtained and the areas with the prevalence of subsidence were determined. Using the time series data of pizometric wells in the period of 2004 to 2020, it was determined that in areas with high land subsidence, there was a decline of several meters in groundwater level, while in areas without land subsidence, changes of groundwater level was in sinusoidal form. Also, with the preparation of water table equilibrium map in the three-year period, the correlation between groundwater level (independent variable) and ground surface displacement (dependent variables) was studied. According to the regression line equation, the statistical relationship was significant and direct relationship between the variables was confirmed. Therefore, regular monitoring of ground water storage and exploitation needs to be on the agenda for an effective mitigation of