SinkholeOdds

Sinkhole risk in Jackson County, MI: 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
32%
At or near the surface
0%
Buried under cover
32%

What to do about a house in Jackson County

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

That works out to roughly 223 of Jackson County's 702 square miles on soluble rock. With about 160,233 residents (228 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 396 map points about 1.3 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 why the 32% under cover still counts.

Counties around Jackson County

The nearest county rated sinkhole country is Barry County, MI, about 51 miles northwest. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

The rock underneath

The largest mapped soluble unit here is the Michigan Formation (black shale), Mississippian in age, covering about 17% of the county. Next is the Bayport Limestone at 15%.

17% of the county sits on gypsum or salt, which dissolves in years rather than millennia. That share matters more than its size suggests.

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 Michigan

Jackson County ranks 46 of 83 in Michigan for soluble rock at the surface, and sits above 0% of US counties on that measure.