Incorporation of InSAR and LandSat ETM+ with CGPS and SVM to assess the subsidence of Mexico City

Abstract This study presents an enhanced analysis of the subsidence rates and their effects on Mexico City. As a result of excess water withdrawal, Mexico City is experiencing subsidence. To analyze this subsidence of Mexico City, we integrated and analyzed Interferometric Synthetic Aperture Radar (InSAR), Continuous Global Positioning Systems (CGPS), and optical remote sensing data. This study utilized 52 ENVISAT-ASAR, nine GPS stations, and one Landsat ETM+ image from the Mexico City area to gather a better understanding of the subsidence rates and its effects on Mexico City’s community The InSAR data covers the period between March 2002 until June 2010, and the GPS data span the period from 1998 until 2012. We find that the maximum of 352-mm change in Line Of Sight (LOS) direction supports the outcomes from previous studies. This study shows that the maximum rate of subsidence in Mexico City is 352 mm/yr. The finding of this study reveals a high amount of correlation (up to 0.98) between two independent geodetic methods. We also implemented the Support Vector Machine (SVM) analysis method based on Landsat ETM+ image to classify Mexico City’s population density. We used SVM to compare Persistent Scatterer Interferometry (PSI) subsidence rates with the buildings’ distribution densities. This study improves the existing method by incorporating 52 ENVISAT images, ETM+, SVM classification, and 9 CGPs. This integrated study shows that the fastest subsidence zone (i.e. areas greater than 100 mm/yr), which falls into the above-mentioned temporal baseline, occurs in the areas of high and moderate building distribution density.