SinkholeOdds

Sinkhole risk in Coke County, TX: Sinkhole country

Sinkhole country

Fast-dissolving gypsum or salt beds under a large part of the county.

On soluble rock
65%
At or near the surface
65%
Buried under cover
0%

What to do about a house in Coke County

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 589 of Coke County's 912 square miles on soluble rock, 589 of them with the rock at or near the surface. With about 3,396 residents (4 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 384 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 Coke County

The closest county with no soluble rock mapped is Archer County, TX, about 165 miles northeast. 1 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 21% of the county. Next is the Whitehorse Group, undivided at 19%.

43% 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

Coke County ranks 29 of 254 in Texas for soluble rock at the surface, and sits above 91% of US counties on that measure.