Two years ago, a giant sinkhole swallowed trees whole in a Louisiana bayou. This year, Nasa says it could have predicted it.

It might sound like too little too late, but with five-to-ten times more sinkholes occurring in this country because of the wet weather this year, any potential tool for mapping precarious landmasses will be most welcome.

The sinkhole Nasa is basing its study on, near Bayou Corne, was a monster measuring 10.1 hectares. It was 229m (751ft) deep by the time it ceased swallowing everything in sight. In a paper published in the journal Geology, Cathleen Jones and Ron Blom, from the Jet Propulsion Laboratory, have shown how radar data captured by Nasa's Uninhabited Airborne Vehicle Synthetic Aperture Radar (UAVSAR) between 2011 and 2012 could have been used to predict the natural catastrophe.

The UAVSAR captures interferometric synthetic aperture radar (InSAR) data—the returning waves the aircraft captures are used to generate digital surface elevation and deformation maps. It's the same technique used to assess fault lines, or even glaciers, capturing incremental changes at the centimeter scale over the course of years.

Although it would seem impossible to predict sinkholes, which happen so suddenly (at least the cover-collapse kind), the groundwork that causes them is being laid over some time. They can occur when rainwater and all the acids it carries permeate the soil to reach soluble rockbeds that are vulnerable, often made from limestone, gypsum, or salts. Over time, chunks begin to erode to create holes and break the connections between the layers. Loose soil layers from above then fill those gaps to create an unstable replacement. Eventually, when these holes and gaps grow too great, this "cover" of soil will collapse. In the case of Bayou Corne, there was also an existing hole to contend with—an underground storage space 914m (2,998ft) below the surface connected to a well—and often sinkholes occur when a natural underground cave already exists.

Those loose soil particles trickling down to the earth below to fill the gaps before the collapse, however, could be a possible sign of danger. And this is essentially what the radar captured—incremental movements in soil particles that over time represent an indicative shift.

The data showed that the surface layer moved 26cm horizontally a month before the collapse, in the direction where the collapse was to occur. These movements were happening in a larger area, stretching around the sinkhole to 500m × 500m.

Although the sinkhole occurred in August 2012, data showed the deformation was still growing in October 2012 and could potentially start inching too close to another underground storage zone.

"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 Jones. "This kind of movement may be more common than previously thought, particularly in areas with loose soil near the surface… At Bayou Corne, it appears that material is continuing to flow into the huge cavern that is undergoing collapse."

The authors conclude in Geology: "This work suggests that InSAR data collected operationally for hazard monitoring could, in some cases, identify sinkhole development before surface collapse and decrease subsequent danger to people and property."

It's a big "could," though. Plenty of other factors come into play with any sinkhole. The large salt dome that sits below the surface at the bayou was being used by companies to store gases and make salt water for local factories, and a class-action lawsuit has since been filed against two of those, Texas Brine and Occidental Chemical. For preventative measures, it might be better to keep a closer eye on manmade practices.

But still, the localized groundshift in the months prior to the collapse do present interesting possibilities for future monitoring. It seems to make sense to monitor regions where natural or manmade underground caves pose a threat.

Coauthor Blom admits: "Our discovery at Bayou Corne was really serendipitous. But it does demonstrate one of the expected benefits of an InSAR satellite that would image wide areas frequently."