Using SAR Imagery to Study Underground Infrastructure

REU: Materials REU | AUTHOR: Daniel Vazquez – University of Alaska, Fairbanks

MENTOR: Jingjing Li – California State University, Los Angeles

ABSTRACT

Synthetic Aperture Radar (SAR) has previously been used in the monitoring and analysis of land uplift or subsidence. Using satellites rather than ground methods we are able to study targets in a more cost-effective and accurate manner. In this study we focus on Mexico City during the years 2017 through 2019. This time period includes the construction of a new metro line as well as a new airport in the central and southwest regions of the city. Our objective is to learn through Sentinel Application Platform (SNAP) software and acquire data from the Sentinel 1A satellite which belongs to the European Space Agency (ESA). We additionally use interferometric methods (InSAR) to study land deformation throughout our chosen time period, We are able to generate phase and intensity diagrams of the study area and after applying noise reduction techniques can convert unwrapped phase results into vertical displacement. Subsidence of up to 33 cm/yr was observed near the Nezahualcoyotl city within Mexico City while the areas surrounding the metro construction averaged 15 cm/yr. While it is possible that underground construction contributed to land subsidence, our results remain unclear as Mexico City also suffers from yearly subsidence due to underwater extraction. In order to improve our accuracy we must further investigate with more satellite images and additional post-processing steps.