Surface Deformation of Los Humeros Caldera, Mexico, Estimated by Interferometric Synthetic Aperture Radar (InSAR).

Abstract:

Los Humeros caldera is located in the eastern part of the Trans-Mexican Volcanic Belt, to the north of the state of Puebla and bordering the west side of the state of Veracruz. The study of the caldera, is of great interest because there is a geothermal field currently working inside of it. In fact, Los Humeros, is the third more important geothermal field in Mexico.

In this work, we used InSAR to estimate the surface deformation on the caldera, aiming to contribute to its modeling and to help preventing subsidence related hazards on the geothermal field and surroundings.

On this study, we calculated 34 interferograms from 21 SAR images of the ENVISAT European Space Agency Mission. The analysis of the interferograms, allow us to detect, decorrelation of the interferometric signal increased, when time spans were greater than 70 days. Also, for those with good signal correlation, the atmospheric signal dominated the interferogram, masking completely the deformation. Moreover, residual orbital ramps were detected, in some of the calculated interferograms. An algorithm capable to remove all the interferogram signal contributions but the deformation related, has been implemented.

Resulting deformation and its correlation with several variables like the geology, the hydrogeology and the seismic records, were analysed through its integration in a Geographic Information System.