Sinkhole risk in Monongalia County, WV: 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: 12%
At or near the surface: 12%
Buried under cover: 0%

What this means before you buy

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

That works out to roughly 42 of Monongalia County's 360 square miles on soluble rock, 42 of them with the rock at or near the surface. With about 108,697 residents (302 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 518 map points about 0.8 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and how these percentages are measured.

Counties around Monongalia County

The nearest county rated sinkhole country is Harrisonburg city, VA, about 104 miles southeast. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Marion County, WV 13 mi southwest · 15% at surface
Greene County, PA 17 mi northwest · 8% at surface
Taylor County, WV 21 mi south · 0% at surface
Preston County, WV 24 mi southeast · 2% at surface
Fayette County, PA 30 mi northeast · 23% at surface
Harrison County, WV 30 mi southwest · 7% at surface

What Monongalia County is built on

The largest mapped soluble unit here is the Monongahela Group (sandstone), Pennsylvanian in age, covering about 11% of the county. Next is the Greenbrier Group at under 1%.

The county also lies over the Michigan Basin; Ohio Basin; Appalachian Basin, 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 West Virginia

Monongalia County ranks 14 of 55 in West Virginia for soluble rock at the surface, and sits above 69% of US counties on that measure.