SinkholeOdds

Sinkhole risk in Sanpete 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
14%
At or near the surface
14%
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 224 of Sanpete County's 1,590 square miles on soluble rock, 224 of them with the rock at or near the surface. With about 30,732 residents (19 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 284 map points about 2.4 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 how these percentages are measured.

Counties around Sanpete County

The nearest county rated sinkhole country is Emery County, UT, about 52 miles southeast. 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 Tertiary (1) sedimentary rocks in southeastern Utah (limestone), Late Paleocene to Early Eocene in age, covering about 13% of the county. Next is the Jurassic (1) sedimentary rocks in central Utah at 1%.

1% 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 Sevire Valley, 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

Sanpete County ranks 10 of 29 in Utah for soluble rock at the surface, and sits above 71% of US counties on that measure.