Sinkhole risk in Ripley County, MO: Sinkhole country

Sinkhole country

Soluble rock at or near the surface across much of the county.

On soluble rock: 95%
At or near the surface: 95%
Buried under cover: 0%

What this means before you buy

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

That works out to roughly 596 of Ripley County's 630 square miles on soluble rock, 596 of them with the rock at or near the surface. With about 10,715 residents (17 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 367 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Ripley County

The closest county with no soluble rock mapped is Clay County, AR, about 32 miles southeast. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Carter County, MO 21 mi north · 100% at surface
Randolph County, AR 23 mi south · 60% at surface
Butler County, MO 27 mi east · 44% at surface
Oregon County, MO 29 mi west · 100% at surface
Clay County, AR 32 mi southeast · 0% at surface
Wayne County, MO 39 mi northeast · 95% at surface

The rock underneath

The largest mapped soluble unit here is the Smithville Dolomite, Powell Dolomite, Cotter Dolomite, Jefferson City Dolomite (dolostone (dolomite)), Early Ordovician-Ibexian Series in age, covering about 47% of the county. Next is the Roubidoux Formation at 43%.

Against the rest of Missouri

Ripley County ranks 36 of 115 in Missouri for soluble rock at the surface, and sits above 98% of US counties on that measure.