Sinkhole risk in Seminole County, OK: Pockets of it

Pockets of it

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

On soluble rock: 34%
At or near the surface: 34%
Buried under cover: 0%

The next step for one property

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 212 of Seminole County's 633 square miles on soluble rock, 212 of them with the rock at or near the surface. With about 23,351 residents (37 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 319 map points about 1.4 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 Seminole County

The nearest county rated sinkhole country is Grady County, OK, about 73 miles west. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Pottawatomie County, OK 20 mi west · 10% at surface
Hughes County, OK 21 mi east · 0% at surface
Okfuskee County, OK 26 mi northeast · 10% at surface
Pontotoc County, OK 31 mi south · 28% at surface
Lincoln County, OK 41 mi northwest · 28% at surface
Cleveland County, OK 41 mi west · 3% at surface

The rock underneath

The largest mapped soluble unit here is the Vanoss Group (shale), Late Pennsylvanian in age, covering about 22% of the county. Next is the Nellie Bly Formation and Hogshooter Limestone at 11%.

Against the rest of Oklahoma

Seminole County ranks 24 of 77 in Oklahoma for soluble rock at the surface, and sits above 81% of US counties on that measure.