SinkholeOdds

Sinkhole risk in Woods County, OK: Sinkhole country

Sinkhole country

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

On soluble rock
42%
At or near the surface
42%
Buried under cover
0%

What to do about a house in Woods County

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

That works out to roughly 534 of Woods County's 1,286 square miles on soluble rock, 534 of them with the rock at or near the surface. With about 8,582 residents (7 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 241 map points about 2.3 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 Woods County

The closest county with no soluble rock mapped is Pratt County, KS, about 64 miles north. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

The rock underneath

The largest mapped soluble unit here is the Flowerpot Shale (shale), Early Permian in age, covering about 23% of the county. Next is the Marlow Formation at 7%.

42% 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 Oklahoma

Woods County ranks 16 of 77 in Oklahoma for soluble rock at the surface, and sits above 85% of US counties on that measure.