Wide-area observations of surface deformation in Mexican urban areas and geothermal fields using ENVISAT InSAR

Abstract

There is an increasingly growing literature on the use of advanced multi-temporal Interferometric Synthetic Aperture Radar (InSAR) to monitor surface deformation with millimeter precision in urban and rural environments, including applications over wide areas spanning hundreds to thousands of square kilometers. In this work, we survey the eastern sector of the Trans-Mexican Volcanic Belt, extending from the state of Hidalgo, through Tlaxcala, Puebla and up to Veracruz, for a total of 19,000 km2. The surveyed area includes both the geothermal exploration site of the Acoculco caldera complex, and Los Humeros geothermal field, one of the largest geothermal exploitation sites of Mexico. Using the multi-temporal Small BAseline Subset (SBAS) InSAR method, we process the whole ENVISAT Advanced SAR (ASAR) IS2 image archive acquired in 2003-2010. Estimated subsidence rates are as high as 3.1 cm/year within the region, and a number of land deformation hotspots are identified within the urban areas of Tulancingo, Tlaxcala and Apizaco, the Tecamachalco valley, as well as within Los Humeros caldera. The surveying of such a scientifically interesting test region provides a proof of concept on how to investigate natural and anthropogenic processes in urban and rural areas using big SAR datasets and InSAR methods.