After going through airborne radar data gathered back in 2012, NASA said it may have the capability of detecting sinkholes before they appear.
Sinkholes have been becoming more common in the past few years and the ability to predict when and where a sinkhole will appear will be very valuable in the future. Sinkholes are large holes in the ground that form when the surface of the earth collapses into an underground cavern. These holes usually occur with little warning and they can pose a danger to both human life and properties.
NASA gathered radar data by scanning the ground in the vicinity of the Louisiana Gulf Coast in an effort to monitor the possible sinking of the ground in certain areas. To gather the data, the agency used in instrument known as an interferometric synthetic aperture radar (InSAR). The special radar was able to take images from an Uninhabited Airborne Vehicle Synthetic Aperture Radar (UAVSAR) drone back in 2011 and 2012. The drone mounted radar is capable of looking for subtle deformations in the ground.
"While horizontal surface deformations had not previously been considered a signature of sinkholes, the new study shows they can precede sinkhole formation well in advance," said NASA researcher Cathleen Jones. "This kind of movement may be more common than previously thought, particularly in areas with loose soil near the surface."
In Aug. 3 2012, a large sinkhole formed in Bayou Corne, Louisiana, prompted the forced evacuation of nearby residents. After the sidewall of an underground cavity collapsed, a large sinkhole suddenly appeared. The sinkhole gradually increased in size and it now covers a 25 acre area. The hole is also around 750 feet deep and it continues to grow in size up until today.
"Our work shows radar remote sensing could offer a monitoring technique for identifying at least some sinkholes before their surface collapse, and could be of particular use to the petroleum industry for monitoring operations in salt domes," said NASA researcher Ron Blom. "Salt domes are dome-shaped structures in sedimentary rocks that form where large masses of salt are forced upward. By measuring strain on Earth's surface, this capability can reduce risks and provide quantitative information that can be used to predict a sinkhole's size and growth rate."
Sinkholes are formed due to human activities, natural phenomenon, or a combination of both. The possibility of a sinkhole suddenly appearing is also increasing during very wet weather conditions. 2014 is expected to be a wet year and scientists are growing more concerned about the increasing likelihood of sinkhole formation in a number of high risk areas.
"This kind of data could be of great value in determining the direction in which the sinkhole is likely to expand," said Jones. "At Bayou Corne, it appears that material is continuing to flow into the huge cavern that is undergoing collapse."