Sinkholes in Wink, Texas, Observed by Satellite Radar Imagery

Two sinkholes in Wink, Texas (Wink Sinks #1, #2), collapsed in 1980 and 2002, respectively. The area where the sinkholes are located in Winkler County, west Texas, is underlain by thick salt beds at depth of about ∼400 m. Anthropogenic activities related to oil and water production have been considered as a primary cause of the sinkhole development and creation. Previous studies have suggested that poor wellbore management, which failed to prevent the intrusion of freshwater and/or unsaturated saltwater into soluble rocks, resulted in the cavity formation, roof failure, and successive upward cavity migration. Interferometric synthetic aperture radar (InSAR) measurements using Advanced Land Observation Satellite Phased Array type L-band Synthetic Aperture Radar and TerraSAR-X images during 2007–2011 and 2015–2016 revealed fine spatial details about the progression of the existing sinkholes and neighboring regions. The immediate vicinities of both existing sinkholes are still subsiding, albeit at a decreasing rate, from ∼18 cm/yr in 2011 to about ∼8 cm/yr in 2016, possibly because of the gradual deposit of the debris from overlying rock formation into the cavity. However, an alarming rate of subsidence can be found ∼1 km east of Wink Sink #2. The peak subsidence rate of this area ranged from ∼40 cm/yr during 2007–2011 to more than 60 cm/yr during 2015–2016. Although the initial trigger of the subsidence feature over the area 1 km east of Wink #2 might be similar to that of Wink Sinks #1 and #2 (i.e., poor borehole management, water-flooding operations in a karst environment), the recent expansion and accelerated subsidence may be attributed to the severe drought in 2011. Continuous monitoring of the subsidence in the broader vicinity of the Wink sinkholes is needed for preventing future catastrophic outcomes of long-term developing geohazards to the area’s oil production facilities, infrastructure, and human safety.