New Mexico's Sinkhole Problem

Manmade, as you might expect:

On a July morning in 2008, the ground below southeastern New Mexico began to shift and crack, shooting a huge plume of dust into the air. Within minutes, a massive sinkhole emerged, which eventually grew to roughly 120 feet deep and 400 feet in diameter.

“At the time, it was an unfortunate situation, but most people considered it to be a one-off,” says Jim Griswold, a special project manager with New Mexico’s Energy, Minerals, and Natural Resources Department. But a few months later, in November, dust once again streamed toward the sky as another similarly sized sinkhole opened, cracking a nearby roadway.

Both holes — and later, a third in Texas — emerged at the site of brine wells, industrial wells through which freshwater is pumped into a subterranean layer of salt. The freshwater mixes with the salt, creating brine, which is brought to the surface for industrial purposes; in this case, oil drilling. After the second sinkhole emerged, Griswold’s department head gave him a new task: Characterize the stability of the state’s 30 other brine wells and report back on where the next crisis might arise.

What he found has been a source of near-constant worry for the past decade. While the first two sinkholes opened in remote areas, the next one, Griswold discovered, could hit the southern edge of Carlsbad: a city of 30,000 people.