Sinkhole risk in Hancock County, TN: Sinkhole country

Sinkhole country

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

On soluble rock: 65%
At or near the surface: 65%
Buried under cover: 0%

What to do about a house in Hancock County

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

That works out to roughly 145 of Hancock County's 222 square miles on soluble rock, 145 of them with the rock at or near the surface. With about 7,038 residents (32 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 434 map points about 0.7 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 Hancock County

The closest county with no soluble rock mapped is Leslie County, KY, about 40 miles north. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Lee County, VA 14 mi northeast · 67% at surface
Hawkins County, TN 17 mi east · 73% at surface
Hamblen County, TN 21 mi south · 99% at surface
Grainger County, TN 23 mi southwest · 79% at surface
Harlan County, KY 23 mi north · 4% at surface
Claiborne County, TN 24 mi west · 75% at surface

Which formation it is

The largest mapped soluble unit here is the Chickamauga Group (limestone), Ordovician in age, covering about 12% of the county. Next is the Maynardville Limestone, Nolichucky Shale, Honaker Dolomite, Maryville Limestone, Rogersville Shale, Rutledge Limestone, Pumpkin Valley Shale at 11%.

Against the rest of Tennessee

Hancock County ranks 37 of 95 in Tennessee for soluble rock at the surface, and sits above 91% of US counties on that measure.