Assessing Collapse Risk in Evaporite Sinkhole-prone Areas Using Microgravimetry and Radar Interferometry

Abstract

Geophysical and remote-sensing methods were applied to better understand sinkhole precursor movement and assess the potential for sinkhole development in evaporitic areas. The approach is illustrated with two examples over bedded salt deposits and a salt dome in Texas, USA. Large sinkholes (90 to 200 m in diameter) formed over Permian bedded salt near Wink in western Texas in June 1980 and May 2002, and on the flank of a coastal-plain salt dome in Daisetta in May 2008. Residents, government officials, and industry representatives wish to better understand the potential for sinkhole formation and growth in both areas. At Wink, limited spatial and temporal data on vertical ground movement from standard surveying has been greatly extended by satellite-based radar interferometry, which was used to delineate areas having recent movement and determine rates of movement. Results from interferometry guided site-specific investigations that included acquisition of high-resolution gravity data, which identified shallow-source mass deficits that indicate potential for continued subsidence or sinkhole formation. At Daisetta, interferometry was used to determine that no detectable subsidence preceded sinkhole collapse (indicating sudden collapse once the upward-migrating void reached a depth that allowed the cohesiveness of overlying semiconsolidated sediments to be overcome), and gravimetry was used to identify other areas where shallow mass deficits exist across the salt dome. Data from both areas can be used to construct risk maps, design comprehensive subsurface investigations, and develop monitoring programs based on repeat radar interferometry and geodetic GPS measurements.

Ongoing Deformation of Sinkholes in Wink, Texas, Observed by Time-Series Sentinel-1A SAR Interferometry (Preliminary Results)

“…The maximum subsidence happens in (d) area (d in Figure 4), at a rate of up to ~13 cm/year. Paine et al [16] observed the deformation (green polygon in Figure 4a) in the same area between January and July, 2007. The deforming area has significantly been stretched in dimensions.…”

“…InSAR has been proven to be a powerful tool for monitoring these sinkhole precursors and post-event deformation in the Dead Sea, Israel [8][9][10][11], Bayou Corne, Louisiana, USA [12], New Mexico [13], and Ebro Valley, Spain [14,15]. Ground subsidence around the sinkholes in Wink, Texas, was measured using a single InSAR image, along with field gravity observations by Paine et al [16]. Despite the success of these previous studies, monitoring sinkhole deformation through InSAR techniques is still challenging, due to the low spatial resolution of synthetic aperture radar (SAR) sensors.…”

“…In contrast, even though both horizontal and vertical deformations are observed at (d) region, the vertical component is the dominant one. Moreover, the sinkhole in Louisiana was activated months prior to collapse, but the deformation in (d) region has been reported for years (at least since 2009 in Paine et al [16]) and the sinkhole collapse has not cropped out yet. This suggests a different mechanism that takes effect on the area underlain by a deep-seated salt bed.…”

Sinkholes and the Engineering and Environmental Impacts of Karst: Proceedings of the Fourteenth Multidisciplinary Conference

“…of Health, 1998 andWilson, 2012). Nitrate concentrations greater than 3 ppm indicates that an aquifer has been impacted by activities on the land surface (Minn. Dept.…”

Automatic Sinkhole Detection from Satellite-based InSAR

“…Paine et. alia [6] utilized InSAR in order to find subsiding locations of interest, then deployed microgravity measurements to further characterize those locations. The addition of microgravimetry to finely characterize potential sinkholes is distinct from our study, where we defer to more generalized field verification carried out by a geologist.…”