The Role of Earth Observation, with a Focus on SAR Interferometry, for Sinkhole Hazard Assessment

Abstract

Sinkholes are global phenomena with significant consequences on the natural-and built environment. Significant efforts have been devoted to the assessment of sinkhole hazards to predict the spatial and temporal occurrence of future sinkholes as well as to detect small-scale deformation prior to collapse. Sinkhole hazard maps are created by considering the distribution of past sinkholes in conjunction with their geomorphic features, controlling conditions and triggering mechanisms. Quantitative risk assessment then involves the statistical analysis of sinkhole events in relation to these conditions with the aim of identifying high risk areas. Remote sensing techniques contribute to the field of sinkhole hazard assessment by providing tools for the population of sinkhole inventories and lend themselves to the monitoring of precursory deformation prior to sinkhole development. In this paper, we outline the background to sinkhole formation and sinkhole hazard assessment. We provide a review of earth observation techniques, both for the compilation of sinkhole inventories as well as the monitoring of precursors to sinkhole development. We discuss the advantages and limitations of these approaches and conclude by highlighting the potential role of radar interferometry in the early detection of sinkhole-induced instability resulting in a potential decrease in the risk to human lives and infrastructure by enabling proactive remediation.

SAR Interferometry for Sinkhole Early Warning and Susceptibility Assessment along the Dead Sea, Israel

“…Collapse sinkholes occur in a large number of geological environments around the globe e.g., [1][2][3]. They generally form by the dissolution of subsurface soluble rocks, creating cavities that collapse when insufficiently supported [4][5][6].…”

Sinkhole susceptibility mapping in Marion County, Florida: Evaluation and comparison between analytical hierarchy process and logistic regression based approaches

“…As aerial images/satellite images used were from 1999 onwards, our approach of identifying sink hole absence may introduce some errors if sinkhole occurred in ‘true absence’ locations before 1999. We suggest that future work on LR modeling of sinkholes should also focus on evaluating truly absent areas of sinkhole occurrence through the use of modern techniques like LiDAR or RADAR 77–79 .…”

InSAR Detection of Localized Subsidence Induced by Sinkhole Activity in Suburban West-Central Florida

“…Detecting a sinkhole before collapse is a difficult task, as sinkholes often display unnoticeable surface changes. Geophysical techniques such as ground penetrating radar (GPR), electrical resistivity tomography (ERT), and shallow seismic surveys (refraction tomography, reflection, surface wave inversion) are commonly used to image with high detail sinkhole characteristics beneath the surface (Dobecki et al, 2006;Theron and Engelbrecht, 2018). However, these techniques require a priori information of sinkhole location and are limited to small study areas (up to hundreds of m 2 ).…”

“…However, these techniques require a priori information of sinkhole location and are limited to small study areas (up to hundreds of m 2 ). Geological and geophysical information is often used for sinkhole hazard and risk assessments, based on modelling and probabilistic approaches (Frumkin et al, 2011;Galve et al, 2011;Kim and Nam, 2014;Theron and Engelbrecht, 2018). Calculated hazard and risk maps rely on sinkhole information that is often incomplete or not available.…”

“…Interferometric Synthetic Aperture Radar (InSAR) technique is a remote sensing technique that can detect surface movements with high detail, while covering vast ar- eas (Massonnet and Feigl, 1998;Bürgmann et al, 2000;Rosen et al, 2000). The technique has been successfully applied to observe sinkhole activity in arid places such as west Texas and the Dead Sea shores (Nof et al, 2013;Atzori et al, 2015;Baer et al, 2018;Kim and Lu, 2018), in urban settings like Heerlen in Netherlands, Gauteng province in South Africa and Quebec City in Canada (Chang and Hanssen, 2014;Theron et al, 2017;Martel et al, 2018) and in vegetated regions like Bayou Corne, Louisiana and Tampa, Florida (Jones and Blom, 2013;Oliver-Cabrera et al, 2019). The above InSAR implementation examples were conducted in areas where interferometric coherence is maintained over long periods of time, through stable radar scattering from bare surfaces, rocks, and man-made structures.…”