SinkholeOdds

Sinkhole risk in Presque Isle County, MI: Pockets of it

Pockets of it

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

On soluble rock
96%
At or near the surface
under 1%
Buried under cover
96%

What to do about a house in Presque Isle 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 635 of Presque Isle County's 659 square miles on soluble rock, 1 of them with the rock at or near the surface. With about 13,230 residents (20 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 578 map points about 1.1 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 why the 96% under cover still counts.

Counties around Presque Isle County

The nearest county rated sinkhole country is Iosco County, MI, about 60 miles south. None of the 6 closest counties land in the same band, so Presque Isle County stands out from its surroundings.

What Presque Isle County is built on

The largest mapped soluble unit here is the Traverse Group (limestone), Middle Devonian in age, covering about 65% of the county. Next is the Dundee Limestone at 22%.

10% 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

Presque Isle County ranks 11 of 83 in Michigan for soluble rock at the surface, and sits above 50% of US counties on that measure.