Sinkhole risk in Salem city, VA: Sinkhole country

What this means before you buy

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 15 of Salem city's 15 square miles on soluble rock, 15 of them with the rock at or near the surface. With about 25,908 residents (1,785 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 525 map points about 0.2 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Salem city

The closest county with no soluble rock mapped is Franklin County, VA, about 22 miles southeast. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

• Roanoke city, VA 5 mi east · 98% at surface
• Roanoke County, VA 8 mi northwest · 33% at surface
• Craig County, VA 16 mi northwest · 34% at surface
• Montgomery County, VA 20 mi west · 64% at surface
• Franklin County, VA 22 mi southeast · under 1% at surface
• Botetourt County, VA 24 mi northeast · 49% at surface

The rock underneath

The largest mapped soluble unit here is the Rome Formation (shale), Cambrian in age, covering about 61% of the county. Next is the Elbrook Formation at 39%.

Against the rest of Virginia

Salem city ranks 2 of 133 in Virginia for soluble rock at the surface, and sits above 99% of US counties on that measure.

• Lexington city 100%
• Roanoke city 98%
• Winchester city 90%
• Bristol city 89%
• Staunton city 89%