SinkholeOdds

Sinkhole risk in Oldham County, TX: Mostly deep or small

Mostly deep or small

Some soluble rock, mostly deeply buried or in a small share of the county.

On soluble rock
2%
At or near the surface
2%
Buried under cover
0%

What to do about a house in Oldham County

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 30 of Oldham County's 1,501 square miles on soluble rock, 30 of them with the rock at or near the surface. With about 1,823 residents (1 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 392 map points about 2.0 miles apart, so a pocket smaller than that can be missed or overstated.

Read next: why gypsum and salt move faster than limestone, and how these percentages are measured.

Counties around Oldham County

The nearest county rated sinkhole country is Briscoe County, TX, about 99 miles southeast. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

What Oldham County is built on

The largest mapped soluble unit here is the Quartermaster Formation and Whitehorse Group, undivided (mixed clastic/carbonate), Permian; Guadalupe Series in age, covering about 2% of the county. Next is the caliche deposits at under 1%.

2% of the county sits on gypsum or salt, which dissolves in years rather than millennia. That share matters more than its size suggests.

The county also lies over the Permian Basin, Anadarko Basin,Dalhart Basin, Palo Duro Basin, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of Texas

Oldham County ranks 136 of 254 in Texas for soluble rock at the surface, and sits above 58% of US counties on that measure.