Sinkhole risk in Manassas city, VA: 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%

What this means before you buy

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

Across 10 square miles, under one square mile of Manassas city maps onto soluble rock. With about 43,616 residents (4,431 per square mile), most of the county is built up, so a mapped unit is likely to sit under somebody's street. The figures come from 468 map points about 0.1 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Manassas city

The nearest county rated sinkhole country is Clarke County, VA, about 37 miles northwest, close enough that the same rock may run under the county line. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Manassas Park city, VA 3 mi northeast · 0% at surface
Prince William County, VA 3 mi south · 2% at surface
Fairfax city, VA 12 mi northeast · 0% at surface
Fairfax County, VA 13 mi northeast · 2% at surface
Fauquier County, VA 18 mi west · under 1% at surface
Falls Church city, VA 19 mi northeast · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Newark Supergroup; Conglomerate, mixed clasts (conglomerate), Triassic in age, covering about under 1% of the county.

Against the rest of Virginia

Manassas city ranks 84 of 133 in Virginia for soluble rock at the surface, and sits above 55% of US counties on that measure.