SinkholeOdds

Sinkhole risk in Seneca County, NY: 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
31%
At or near the surface
0%
Buried under cover
31%

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 99 of Seneca County's 324 square miles on soluble rock. With about 32,650 residents (101 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 604 map points about 0.7 miles apart, so a pocket smaller than that can be missed or overstated.

Read next: why gypsum and salt move faster than limestone, and why the 31% under cover still counts.

Counties around Seneca County

The nearest county rated sinkhole country is Union County, PA, about 126 miles south. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Which formation it is

The largest mapped soluble unit here is the Camillus and Syracuse Formations (shale), Upper Silurian in age, covering about 15% of the county. Next is the Onondaga Limestone at 9%.

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 New York

Seneca County ranks 50 of 62 in New York for soluble rock at the surface, and sits above 0% of US counties on that measure.