Texas currently has two massive sinkholes located about 1 mile apart between the towns of Wink and Kermit.
The first sinkhole near the Hendricks oil well 10-A was formed in 1980, while the other sinkhole opened up 22 years later in 2002 near Gulf WS-8 supply well.
Sinkholes can form naturally, but they also form as a result of human activity. The so-called Wink Sinks were created as a result of oil and gas extraction in the region, which peaked from 1926 to 1964.
Residents of Wink and Kermit may have been used to the presence of the couple of holes in their ground, but findings of a new study suggest that the two sinkholes are expanding, and there's a possibility that they will converge to form one bigger hole.
Researchers from Southern Methodist University looked at radar images of the sinkholes taken by an orbiting space satellite. Using a technique known as interferometric synthetic aperture radar, or InSAR, to detect changes that are not visible to people at ground level, the researchers found that the sinkholes are unstable with the ground around them subsiding.
The findings indicate a possibility that new sinkholes could form or the existing holes would converge into one gigantic sinkhole.
"Our results indicate that the sinkholes are still influenced by ground depression, implying that the sinkholes continue to expand," study researcher Jin-Woo Kim, from the Southern Methodist University in Dallas, and colleagues reported.
"A region 1 km northeast of sinkhole #2 is sinking at a rate of up to 13 cm/year, and its aerial extent has been enlarged in the past eight years when compared with a previous survey."
The assessment also raises safety concerns. The area included in the geohazard map has communities. It is also heavily populated with gas and oil production equipment and installations as well as hazardous liquid pipelines.
"A collapse could be catastrophic. Following our study, we are collecting more high-resolution satellite data over the sinkholes and neighboring regions to monitor further development and collapse," said Kim.
Groundwater levels, and dissolving minerals appear to be associated with the unstable ground in the area.
Sinkholes are often formed when a layer of rock underneath the ground gets dissolved by acidic water. Rainfall that gets through the soil absorbs carbon dioxide and reacts with decaying vegetation so water that reaches the soluble rock is already acidic.
Researchers have observed that when groundwater levels rise, the ground rises as well, but the same groundwater speeds up the dissolving of interbedded salt layers that causes the ground surface to subside.
Photo: Nicolas Henderson | Flickr
