Sinkhole risk in Izard County, AR: Sinkhole country

Sinkhole country

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

On soluble rock: 100%
At or near the surface: 100%
Buried under cover: 0%

The next step for one property

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

That works out to roughly 580 of Izard County's 580 square miles on soluble rock, 580 of them with the rock at or near the surface. With about 14,291 residents (25 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 283 map points about 1.4 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Izard County

The closest county with no soluble rock mapped is Cleburne County, AR, about 35 miles south. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Fulton County, AR 20 mi north · 100% at surface
Stone County, AR 21 mi southwest · 39% at surface
Sharp County, AR 25 mi east · 100% at surface
Baxter County, AR 27 mi northwest · 96% at surface
Independence County, AR 32 mi southeast · 41% at surface
Cleburne County, AR 35 mi south · 0% at surface

Which formation it is

The largest mapped soluble unit here is the St. Peter Sanstone and Everton Formation (Middle Ordovician) (sandstone), Middle Ordovician in age, covering about 66% of the county. Next is the Powell Dolomite at 19%.

Against the rest of Arkansas

Izard County ranks 1 of 75 in Arkansas for soluble rock at the surface, and sits above 99% of US counties on that measure.