Sinkhole risk in Nevada County, AR: 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 Nevada County

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

That works out to roughly 40 of Nevada County's 618 square miles on soluble rock, 40 of them with the rock at or near the surface. With about 8,004 residents (13 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 323 map points about 1.4 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Nevada County

The nearest county rated sinkhole country is Adair County, OK, about 172 miles northwest. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Hempstead County, AR 21 mi west · 43% at surface
Ouachita County, AR 25 mi east · 0% at surface
Clark County, AR 28 mi north · 21% at surface
Columbia County, AR 31 mi south · 0% at surface
Lafayette County, AR 34 mi southwest · 0% at surface
Pike County, AR 40 mi northwest · 15% at surface

Which formation it is

The largest mapped soluble unit here is the Arkadelphia Marl (mixed clastic/carbonate), Late Cretaceous in age, covering about 4% of the county. Next is the Nacatoch Sand at 3%.

The county also lies over the Gulf Coast salt domes, 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 Arkansas

Nevada County ranks 31 of 75 in Arkansas for soluble rock at the surface, and sits above 64% of US counties on that measure.