Sinkhole risk in Throckmorton 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: 37%
At or near the surface: 37%
Buried under cover: 0%

What to do about a house in Throckmorton County

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 337 of Throckmorton County's 913 square miles on soluble rock, 337 of them with the rock at or near the surface. With about 1,532 residents (2 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 396 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Throckmorton County

The nearest county rated sinkhole country is Haskell County, TX, about 30 miles west, close enough that the same rock may run under the county line. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Haskell County, TX 30 mi west · 50% at surface
Young County, TX 31 mi east · 2% at surface
Shackelford County, TX 31 mi south · 54% at surface
Baylor County, TX 31 mi north · 50% at surface
Stephens County, TX 37 mi southeast · 13% at surface
Archer County, TX 43 mi northeast · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Lueders Formation (shale), Permian; Leonard Series in age, covering about 14% of the county. Next is the Bead Mountain Formation at 8%.

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

Against the rest of Texas

Throckmorton County ranks 72 of 254 in Texas for soluble rock at the surface, and sits above 82% of US counties on that measure.