Sinkhole risk in Carson County, TX: Not karst, but voids possible

Not karst, but voids possible

No soluble bedrock; some pseudokarst (piping or lava-tube ground).

On soluble rock: under 1%
At or near the surface: under 1%
Buried under cover: 0%

What this means before you buy

Not true karst, but soil piping or lava tubes can still open voids - mention it to an inspector.

That works out to roughly 7 of Carson County's 920 square miles on soluble rock, 7 of them with the rock at or near the surface. With about 5,822 residents (6 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.

Worth reading for this county: why gypsum and salt move faster than limestone, and how ground with no limestone still opens up.

Counties around Carson County

The nearest county rated sinkhole country is Donley County, TX, about 44 miles southeast. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Hutchinson County, TX 30 mi north · 12% at surface
Potter County, TX 30 mi west · 11% at surface
Armstrong County, TX 30 mi south · 27% at surface
Gray County, TX 31 mi east · 2% at surface
Roberts County, TX 42 mi northeast · 0% at surface
Moore County, TX 42 mi northwest · 6% at surface

What Carson 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 under 1% of the county.

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

Carson County ranks 139 of 254 in Texas for soluble rock at the surface, and sits above 54% of US counties on that measure.