Integration of differential InSAR and GPS measurements for studying of surface deformation

In the following work we propose a new technique for combing two complementary geodetic data sets: Differential Synthetic Aperture Radar (DInSAR) and Global Positioning System (GPS). This technique is based on analytical optimization of the Gibbs energy function which is constructed for the case when neighboring points on the ground are considered independent. In this case the energy function can be greatly simplified and the solution can be found by the inversion of a set of three linear equations.; The first part of this work presents the results of the computer simulations which were undertaken in order to estimate the accuracy of the technique. In Chapter 2, a three-dimensional velocity field was reconstructed from synthetic, sparse GPS observations and two differential InSAR interferograms (ascending and descending). The improvement in accuracy of the optimized velocity field was significantly greater than for other similar known techniques, while at the same time the computational time was significantly lower (minutes in comparison to days).; In Chapter 3, this DInSAR-GPS optimization technique is used to investigate the velocity field of the southern California region near Los Angeles. The GPS data from SCIGN and one DInSAR interferogram were used to perform the optimization. The results of the optimization revealed a strong shortening effect across the region with the high degree of accuracy. Also a few areas of subsidence due to groundwater extraction were confirmed as has been suggested by previous investigations and the value of the subsidence was estimated.; In Chapter 4, the technique was applied to investigate the creep motion of the southern San Andreas fault around the Salton Sea. Previous works suggest that the fault in that region creeps with constant velocity in a horizontal strike slip direction. This work, however, suggests that either the creep velocity is not constant over time or the motion is not completely horizontal. These conclusions are derived from the analysis of two velocity fields for 1992-1998 and 1997-2001 which show different signals.; Chapter 5 presents preliminary results for the modification of the GPS-DInSAR optimization performed for campaign GPS and ENVISAT DInSAR data on Tenerife island. The goal of this work is to fuse both geodetic data sets, observe surface deformations and better characterize potential precursors of volcanic activity. Five runs were performed for time periods spanning from 2002 until 2006 with the interval of one year. Currently there are no strong surface deformations associated with possible future eruption identified in the areas of interest, however, some inversion studies will be performed in the near future in order to provide more definite answers.; Finally, the source of errors is analyzed and suggestions for improvement of the technique are made.