SinkholeOdds

Sinkhole risk in Rich County, UT: 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
9%
At or near the surface
9%
Buried under cover
0%

The next step for one property

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

That works out to roughly 95 of Rich County's 1,029 square miles on soluble rock, 95 of them with the rock at or near the surface. With about 2,752 residents (3 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 306 map points about 1.8 miles apart, so a pocket smaller than that can be missed or overstated.

Read next: why gypsum and salt move faster than limestone, and how these percentages are measured.

Counties around Rich County

The nearest county rated sinkhole country is Emery County, UT, about 183 miles south. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

The rock underneath

The largest mapped soluble unit here is the Jurassic (1) sedimentary rocks in Salt Lake City-Coalville-Randolph region (limestone), Middle to Late Jurassic in age, covering about 2% of the county. Next is the Jurassic (1) sedimentary rocks in Salt Lake City-Coalville-Randolph region at 2%.

2% 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 Wyoming Thrust belt, 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 Utah

Rich County ranks 17 of 29 in Utah for soluble rock at the surface, and sits above 67% of US counties on that measure.