Sinkhole risk in Greene County, TN: Sinkhole country

Sinkhole country

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

On soluble rock: 88%
At or near the surface: 88%
Buried under cover: 0%

What to do about a house in Greene County

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

That works out to roughly 547 of Greene County's 622 square miles on soluble rock, 547 of them with the rock at or near the surface. With about 73,398 residents (118 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 586 map points about 1.0 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 Greene County

The closest county with no soluble rock mapped is Yancey County, NC, about 36 miles southeast. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Hawkins County, TN 19 mi north · 73% at surface
Washington County, TN 21 mi east · 88% at surface
Madison County, NC 23 mi south · 3% at surface
Hamblen County, TN 23 mi west · 99% at surface
Cocke County, TN 24 mi southwest · 50% at surface
Unicoi County, TN 25 mi east · 11% at surface

Which formation it is

The largest mapped soluble unit here is the Sevier Shale (shale), Ordovician in age, covering about 39% of the county. Next is the Knox Group at 32%.

Against the rest of Tennessee

Greene County ranks 15 of 95 in Tennessee for soluble rock at the surface, and sits above 96% of US counties on that measure.