Sinkhole risk in Greeley County, KS: Mostly deep or small

Mostly deep or small

Some soluble rock, mostly deeply buried or in a small share of the county.

On soluble rock: 7%
At or near the surface: 7%
Buried under cover: 0%

What to do about a house in Greeley County

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 51 of Greeley County's 778 square miles on soluble rock, 51 of them with the rock at or near the surface. With about 1,152 residents (1 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 399 map points about 1.4 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 these percentages are measured.

Counties around Greeley County

The nearest county rated sinkhole country is Clark County, KS, about 139 miles southeast. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Wichita County, KS 25 mi east · 13% at surface
Wallace County, KS 31 mi north · 23% at surface
Hamilton County, KS 34 mi south · 5% at surface
Kearny County, KS 43 mi southeast · 2% at surface
Logan County, KS 46 mi northeast · 11% at surface
Prowers County, CO 48 mi southwest · 35% at surface

Which formation it is

The largest mapped soluble unit here is the Ogallala Formation (arkose), Miocene in age, covering about 7% 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 Kansas

Greeley County ranks 77 of 105 in Kansas for soluble rock at the surface, and sits above 64% of US counties on that measure.