SinkholeOdds

Sinkhole risk in Sedgwick County, KS: Pockets of it

Pockets of it

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

On soluble rock
16%
At or near the surface
16%
Buried under cover
0%

What to do about a house in Sedgwick 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 161 of Sedgwick County's 997 square miles on soluble rock, 161 of them with the rock at or near the surface. With about 536,081 residents (538 per square mile), most of the county is built up, so a mapped unit is likely to sit under somebody's street. The figures come from 360 map points about 1.7 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why gypsum and salt move faster than limestone, and the signs to look for and how an inspection works.

Counties around Sedgwick County

The nearest county rated sinkhole country is Harper County, KS, about 48 miles southwest. 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 Sumner Group (shale), Late Permian - Cimarronian in age, covering about 16% of the county.

16% 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 Kansas

Sedgwick County ranks 64 of 105 in Kansas for soluble rock at the surface, and sits above 72% of US counties on that measure.