Analysis of Spatial and Temporal Evolution of the Ground Deformation in the Cerro Prieto Geothermal Field (Mexicali Valley, B.C., Mexico) Using DInSAR and Leveling Data.

Abstract

Geodetic monitoring of the Cerro Prieto Geothermal Field (Mexicali Valley, B.C., Mexico) and the surrounding area has been historically carried out with ground-based surveys. These surveys provide information only at a number of measuring points. The surveys are time-consuming and expensive and restricted by available resources. These limitations could be relieved by exploiting the satellite-based differential interferometry (DInSAR) which allows the extraction of geodetic information over wide area and yielding improved coverage in comparison with the mean repetition time of the campaign measurements.
Recent results from Cerro Prieto Geothermal Field (CPGF), obtained from ENVISAT ASAR descending data from October 2003 – March 2006 are shown in this work. The results reveal that the area of the CPGF is continuously subsiding. A stack of 4 interferograms spanning the 350 day time-period between December 2004 and December 2005 indicates a maximum subsidence velocity of at least 15 cm/yr. Comparison of subsidence maps obtained from DInSAR data for the indicated period and from leveling data for the 1994-1997 period allows the evaluation of changes both in the spatial pattern and in the rate of subsidence. These changes are compared to the production development in the CPGF.