Space-Based Detection of Sinkhole Activity in Central Florida

Abstract:

Central Florida's thick carbonate deposits and hydrological conditions have made the area prone to sinkhole development. Sinkhole collapse is a major geologic hazard in central Florida threatening human life and causing substantial damage to property. According to the Florida Senate report in 2010, between 2006-2010 total insurance claims due to sinkhole activity were around $200 million per year. Detecting sinkhole deformation before a collapse is a very difficult task, due to small or sometimes unnoticeable surface changes. Most techniques used to monitor sinkholes provide very localized information and cannot be implemented to study broad areas. This is the case of central Florida, where the active zone spans over hundreds of square-kilometers.

In this study we use Interferometric Synthetic Aperture Radar (InSAR) observations acquired over several locations in central Florida to detect possible pre-collapse deformation. The study areas were selected because they have shown suspicious sinkhole behavior. One of the sites collapsed on March 2013 destroying a property and killing a man. To generate the InSAR results we use six datasets acquired by the TerraSAR-X and Cosmo-SkyMed satellites with various acquisition modes reflecting pixel resolutions between 25cm and 2m. Preliminary InSAR results show good coherence over constructed areas and low coherence in vegetated zones, justifying our analysis that focuses on the man-made structures. After full datasets will be acquired, a Persistent Scatterer Interferometry (PSI) time series analysis will be performed for detecting localized deformation at spatial scale of 1-5 meters. The project results will be verified using Ground Penetrating Radar.