Sinkhole risk in Las Animas County, CO: Pockets of it

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 1,375 of Las Animas County's 4,773 square miles on soluble rock, 1,375 of them with the rock at or near the surface. With about 14,518 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 299 map points about 4.0 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 the signs to look for and how an inspection works.

Counties around Las Animas County

The nearest county rated sinkhole country is Clark County, KS, about 233 miles east. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

• Otero County, CO 43 mi northeast · 42% at surface
• Huerfano County, CO 56 mi northwest · 23% at surface
• Colfax County, NM 59 mi southwest · 6% at surface
• Pueblo County, CO 63 mi north · 45% at surface
• Union County, NM 65 mi southeast · 14% at surface
• Bent County, CO 68 mi northeast · 44% at surface

What Las Animas County is built on

The largest mapped soluble unit here is the Carlile Shale, Greenhorn Limestone, and Graneros Shale (shale), Cretaceous in age, covering about 14% of the county. Next is the Niobrara Fm at 12%.

The county also lies over the Permian Basin, Anadarko Basin,Dalhart Basin, Palo Duro 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 Colorado

Las Animas County ranks 6 of 64 in Colorado for soluble rock at the surface, and sits above 79% of US counties on that measure.

• Pueblo County 45%
• Bent County 44%
• Otero County 42%
• Prowers County 35%
• Kiowa County 30%