Sinkhole risk in Tazewell County, VA: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 43%
At or near the surface: 43%
Buried under cover: 0%

The next step for one property

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 225 of Tazewell County's 519 square miles on soluble rock, 225 of them with the rock at or near the surface. With about 38,875 residents (75 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 509 map points about 1.0 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why gypsum and salt move faster than limestone, and the signs to look for and how an inspection works.

Counties around Tazewell County

The nearest county rated sinkhole country is Smyth County, VA, about 20 miles south, close enough that the same rock may run under the county line. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

McDowell County, WV 19 mi north · 0% at surface
Smyth County, VA 20 mi south · 55% at surface
Bland County, VA 24 mi east · 31% at surface
Buchanan County, VA 28 mi west · 0% at surface
Wythe County, VA 31 mi southeast · 64% at surface
Mercer County, WV 32 mi northeast · 39% at surface

What Tazewell County is built on

The largest mapped soluble unit here is the Moccasin or Bays Formation through Blackford Formation (shale), Ordovician in age, covering about 16% of the county. Next is the Knox Group at 12%.

The county also lies over the Saltville, Virginia, 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 Virginia

Tazewell County ranks 28 of 133 in Virginia for soluble rock at the surface, and sits above 85% of US counties on that measure.