Sinkhole risk in Fulton 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%

What to do about a house in Fulton County

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

That works out to roughly 616 of Fulton County's 618 square miles on soluble rock, 616 of them with the rock at or near the surface. With about 12,546 residents (20 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 381 map points about 1.3 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 Fulton County

The closest county with no soluble rock mapped is Cleburne County, AR, about 55 miles south. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Izard County, AR 20 mi south · 100% at surface
Sharp County, AR 24 mi southeast · 100% at surface
Howell County, MO 27 mi north · 100% at surface
Baxter County, AR 29 mi west · 96% at surface
Oregon County, MO 31 mi northeast · 100% at surface
Ozark County, MO 40 mi northwest · 100% at surface

What Fulton County is built on

The largest mapped soluble unit here is the Cotter and Jefferson City Dolomites (dolostone (dolomite)), Early Ordovician in age, covering about 79% of the county. Next is the Powell Dolomite at 10%.

Against the rest of Arkansas

Fulton County ranks 3 of 75 in Arkansas for soluble rock at the surface, and sits above 99% of US counties on that measure.