Sinkhole risk in Luzerne County, PA: 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: 2%
At or near the surface: 0%
Buried under cover: 2%

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 16 of Luzerne County's 890 square miles on soluble rock. With about 331,379 residents (372 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 276 map points about 1.8 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 Luzerne County

The nearest county rated sinkhole country is Union County, PA, about 58 miles west. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Carbon County, PA 23 mi southeast · under 1% at surface
Columbia County, PA 24 mi west · 4% at surface
Wyoming County, PA 24 mi north · 0% at surface
Lackawanna County, PA 26 mi northeast · 0% at surface
Sullivan County, PA 33 mi northwest · 0% at surface
Monroe County, PA 35 mi east · under 1% at surface

Which formation it is

The largest mapped soluble unit here is the Hamilton Group (shale), Devonian in age, covering about 1% of the county. Next is the Onondaga and Old Port Formations, undivided 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 Pennsylvania

Luzerne County ranks 56 of 67 in Pennsylvania for soluble rock at the surface, and sits above 0% of US counties on that measure.