SinkholeOdds

Sinkhole risk in Riverside County, CA: No soluble rock mapped

No soluble rock mapped

No soluble bedrock mapped.

On soluble rock
under 1%
At or near the surface
under 1%
Buried under cover
0%

The next step for one property

No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.

That works out to roughly 65 of Riverside County's 7,209 square miles on soluble rock, 65 of them with the rock at or near the surface. With about 2,529,933 residents (351 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 341 map points about 4.6 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 Riverside County

The nearest county rated sinkhole country is Emery County, UT, about 468 miles northeast. 3 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 Paleozoic marine rocks, undivided, unit 1 (Mojave Desert and Death Valley area) (limestone), Late Proterozoic to Jurassic in age, covering about under 1% of the county. Next is the Limestone of probable Paleozoic or Mesozoic age at under 1%.

The county also lies over the Salton Trough, 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 California

Riverside County ranks 19 of 58 in California for soluble rock at the surface, and sits above 55% of US counties on that measure.