Sinkhole risk in Centre County, PA: Pockets of it

Pockets of it

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

On soluble rock: 40%
At or near the surface: 40%
Buried under cover: 0%

What to do about a house in Centre County

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 442 of Centre County's 1,107 square miles on soluble rock, 442 of them with the rock at or near the surface. With about 159,805 residents (144 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 454 map points about 1.6 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 Centre County

The nearest county rated sinkhole country is Union County, PA, about 42 miles east. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Mifflin County, PA 24 mi southeast · 45% at surface
Clinton County, PA 25 mi northeast · 21% at surface
Clearfield County, PA 34 mi west · under 1% at surface
Huntingdon County, PA 34 mi south · 35% at surface
Juniata County, PA 35 mi southeast · 45% at surface
Blair County, PA 37 mi southwest · 36% at surface

Which formation it is

The largest mapped soluble unit here is the Mauch Chunk Formation (shale), Mississippian in age, covering about 11% of the county. Next is the Coburn Formation through Nealmont Formation, undivided at 5%.

Against the rest of Pennsylvania

Centre County ranks 7 of 67 in Pennsylvania for soluble rock at the surface, and sits above 84% of US counties on that measure.