In west Texas, they call them the "Wink Sinks." They're two giant sinkholes between the towns of Wink and Kermit, the after-affect of a lot of oil being pumped out of the ground in the area more than 60 years ago. And now researchers have discovered that the oddball landmarks -- already the size of multiple football fields -- are unstable and likely to grow even bigger.
Southern Methodist University geophysicists utilized a time series of radar images captured by an orbiting satellite 435 miles overhead to study the sinkholes. They used a technique called interferometric synthetic aperture radar, or InSAR, to detect changes that aren't visible to a person at ground level.
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Their study, published in the journal Remote Sensing, found that the extent of subsidence in the area has increased significantly over the past seven years, and that the instability originally caused by oil drilling now is being driven by changing groundwater levels.
As the groundwater increases, it dissolves a massive underground salt formation in the area, which then causes the ground to sink.
That's a problem, because the Wink Sinks already are pretty big. Wink Sink No. 1, which is closer to the town of Kermit, has grown since 1980 to 361 feet across. Wink Sink No. 2, which is nine-tenths of a mile to the south, is about 900 feet across at its widest point.
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But to make matters worse, other parts of the area around the sinkholes is sinking as well. The highest rate of ground subsidence is in an area about seven-tenths of a mile northeast of No. 2, which is collapsing at a rate of more than 5 inches per year.
"This area is heavily populated with oil and gas production equipment and installations, hazardous liquid pipelines, as well as two communities," research scientist Jin-Woo Kim, who co-authored the study with SMU professor Zhong Lu, explained in a press release. He explained that a more massive collapse "could be catastrophic."
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