An assessment of DInSAR potential for simulating geological subsurface structure

There are three main focus areas in this research: the monitoring of surface deformation, the simulation of the subsurface structure, and the retrieval of the required subsurface parameters through the use of remotely sensed surface observations to improve the available structural models. To achieve these goals, as an initial step the areas which are susceptible to surface deformation due to ground water extraction are pinpointed using Multidimensional Small Baseline Subset (MSBAS) technique for interferometric pairs of C-, L- and Xband SAR datasets. These observations identify the potential regions for any geological boundaries such as faults or changes in the formation sequence which may have an impact on observed vertical and horizontal deformation signals. For the next stage, it is proposed that these observations could be applied for geophysical inverse modelling to assess the temporal behaviour and impact of boundaries for the observed deformation. By estimating the best parameter space through inverse modelling, it is hypothesized that the previously available subsurface structural model provided by integration of multiple geophysical datasets like seismic, gravity, radiometric and magnetic, may be improved in conjunction with SAR interferometry. For the Surat Basin, preliminary DInSAR results (ERS-Envisat C-band; 1992 to 2005) show considerable deformation patterns in 2004-2005. These signals are still present in the 2012-2013 interferograms and are coincident with regional underground activities, confirming the anthropogenic impact on subsidence. While this is a promising development, accurate and long term measurement of deformation using such sparse satellite dataset is still difficult to achieve and a more advanced DInSAR processing algorithm for integrating various space-borne SAR data with different acquisition parameters (i.e. temporal sampling, spatial resolution, wave-band and polarization, etc.) is required. This will improve the temporal and spatial resolution of the interferograms. In this study, first results of the DInSAR processing chain over the Surat Basin, including a discussion on the optimization scheme layout are proposed for future use.