Eight years of Mexico City Subsidence Monitoring and Analysis Aided by InSAR and GIS Tools
Lopez-Quiroz, Penelope1; Carreon-Freyre, Dora2; Cerca, Mariano2; Doin, Marie-Pierre3
1Centro de Geociencias UNAM, MEXICO; 2CGEO UNAM, MEXICO; 3ISTERRE, FRANCE
In this work we show, the achievements in the monitoring and analysis of Mexico city subsidence aided by InSAR. Resulting from a Small Baseline Processing technique of 53 ENVISAT images, spanning the 2002-2010 study period, we have derived the subsidence time series for each pixel covering 30 x 30 m over the Mexico city metropolitan area. Mean annual subsidence rates have also been calculated, showing Nezahualcoyotl and Chalco as the districts with highest annual subsidence rates (~40 cm/yr). In most of the analyzed pixels, the time series showed an almost perfect subsidence linear behavior. However, in some pixels mapping different areas of the city, a small quadratic component, associated to subsidence acceleration or deceleration, has been detected. A Geographic Information System of the Mexico's Basin (where Mexico city is located) has been integrated to analyze different phenomena related to subsidence. The Mexico's Basin GIS, contains among several information layers, the Digital Elevation Model of the Basin, the geology of the Basin, the geotechnical zonification, piezometric levels evolution and some mapped fractures and faults. As an example, the Iztapalapa's case, one of the most popular and populated districts of Mexico city, will be presented, where a correlation between subsidence acceleration and fractures has been detected and analyzed.