SinkholeOdds

Sinkhole risk in Nolan County, TX: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock
66%
At or near the surface
66%
Buried under cover
0%

What this means before you buy

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 602 of Nolan County's 912 square miles on soluble rock, 602 of them with the rock at or near the surface. With about 14,182 residents (16 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 388 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and the signs to look for and how an inspection works.

Counties around Nolan County

The nearest county rated sinkhole country is Fisher County, TX, about 30 miles north, close enough that the same rock may run under the county line. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Which formation it is

The largest mapped soluble unit here is the Edwards Limestone (limestone), Early Cretaceous in age, covering about 43% of the county. Next is the Whitehorse Group, undivided at 11%.

20% 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

Nolan County ranks 28 of 254 in Texas for soluble rock at the surface, and sits above 92% of US counties on that measure.