OPTIMIZED IMAGING OF SINKHOLES WITH 3D GPR IN COVERED KARST TERRAIN BY USE OF FDTD MODELING

Ground penetrating radar (GPR) is widely used to identify locations of sinkholes in covered karst terrain in Florida. Here we address the capabilities of GPR for doing more than identifying the presence of sinkholes, specifically for resolving detailed structure within sinkholes at a level that may be useful for understanding the hydrologic role of the sinkholes. The ultimate goal is to identify optimal survey configurations for maximizing the recovery of hydrologically relevant information. Simulations of 3D GPR surveys over sinkholes in covered karst terrain are run using the finite-difference time-domain (FDTD) program GPRMax. Results from the synthetic surveys are then processed with standard techniques, including migration. Preliminary results will be presented from a suite of models designed to examine the resolution limits of surveys as a function of survey density, antenna frequencies, antenna orientations, and accuracy in spatial positioning.