Sinkhole risk in Lane County, OR: Not karst, but voids possible

Not karst, but voids possible

No soluble bedrock; some pseudokarst (piping or lava-tube ground).

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

What this means before you buy

Not true karst, but soil piping or lava tubes can still open voids - mention it to an inspector.

Across 4,554 square miles, under one square mile of Lane County maps onto soluble rock. With about 382,396 residents (84 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 266 map points about 4.1 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: how ground with no limestone still opens up, and how these percentages are measured.

Counties around Lane County

The nearest county rated sinkhole country is Emery County, UT, about 715 miles southeast. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Linn County, OR 43 mi northeast · 0% at surface
Douglas County, OR 46 mi south · 1% at surface
Benton County, OR 47 mi northwest · 0% at surface
Marion County, OR 69 mi north · 0% at surface
Lincoln County, OR 70 mi northwest · 0% at surface
Polk County, OR 72 mi north · 3% at surface

Against the rest of Oregon

Lane County ranks 25 of 36 in Oregon for soluble rock at the surface, and sits above 0% of US counties on that measure.