Sinkhole risk in Lassen County, CA: 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 to do about a house in Lassen County

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

Across 4,541 square miles, under one square mile of Lassen County maps onto soluble rock. With about 28,340 residents (6 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 263 map points about 4.2 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: how ground with no limestone still opens up, and how these percentages are measured.

Counties around Lassen County

The nearest county rated sinkhole country is Emery County, UT, about 538 miles east. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Washoe County, NV 50 mi east · 2% at surface
Plumas County, CA 51 mi south · 0% at surface
Modoc County, CA 61 mi north · 0% at surface
Shasta County, CA 75 mi west · 9% at surface
Sierra County, CA 79 mi south · 0% at surface
Butte County, CA 89 mi southwest · under 1% at surface

Against the rest of California

Lassen County ranks 37 of 58 in California for soluble rock at the surface, and sits above 0% of US counties on that measure.