Application of radar interferometry in the study of subsidence in the Toluca Valley, Mexico

Abstract

The Toluca Valley Aquifer belongs to High Lerma River Basin in Mexico State, showed the second most over exploited aquifer of Mexico. At present, the resource extraction had caused negative impacts like subsidence processes whose induce fissures as many urban zones as industrial zones, thus involving a geological and soil compression in the design zone.

The objective was to evaluate subsidence processes in the Toluca Valley, since interferometric differential techniques who enable to precisely estimation of the land velocity deformation.

In fact it applied the radar interferometric method (InSAr) well-known like “Persistent Scatterer” (PS), to major precision. On difference of DinSAR, PS allows pixels selection who shows major quality in his amplitude and phase (bright radar targets) beginning from manifolds SAR dates. Were obtained 30 ENVISAT-ASAR images thus in Single Light Complex (SLC) mode, for 2003-2010 period, with rank-acimut resolution of 20.16 x 24.34.

The results show deformation velocities upper 50 mm/year with great limits as many as to 200 mm/year. In spatial terms, the great subsidence processes correspond to the central basin zone, coinciding with historic center of Toluca city, like than east of basin in zones cultivation and swamps. For work validation it analyzed the superficial aquifer decrease level since piezometric dates and her stratigraphic relationship in field. Whatever, it found a direct relationship between affected zones of subsidence in agreement with PS and registered points with major aquifer low spirits in record with depth static level of ground.

Revista Ciencias Espaciales, Volumen 8, Número 1 Primavera, 2015; 294-309