USGS Karst Sinkhole Risk Screener — Geohazard by Coordinate

Batch karst and pseudokarst susceptibility screen. Send a list of coordinates, get back a point-in-polygon check against all 7 relevant layers of the USGS CONUS_Karst compilation (the national soluble-rock/karst map behind USGS Open-File Report 2014-1156, Weary & Doctor) — carbonate karst, evaporite karst, sandstone karst, subsurface evaporite basins, a broad gypsum extent, and two non-carbonate pseudokarst mechanisms (soil piping, volcanic lava tubes). Each asset gets a plain-English risk note, a sinkhole_risk_context tier (Elevated / Moderate / None mapped), and a geotech_phase1_flag for due-diligence checklists.

Be honest about what this is: this is a regional geology susceptibility screen, not a site-specific sinkhole prediction, a geotechnical investigation, or an insurance/engineering determination. USGS karst polygons are drawn at state/formation scale. A "clear" result does not rule out an undocumented local sinkhole. A "hit" does not mean collapse is imminent. Every row carries a disclaimer field saying exactly that — read it before you build anything on top of this actor's output.

Who this is for

• Phase-I ESA / environmental consultants — karst and sinkhole potential is a standard checklist item (ASTM E1527); this turns a manual USGS map lookup into a batch API call.
• Geotechnical engineers & CRE lenders — flag a portfolio of sites for soluble-bedrock foundation risk before ordering a full subsurface investigation.
• Sinkhole/subsidence insurance underwriters (especially FL, TX, MO, PA, TN, KY) — a fast first-pass screen ahead of full underwriting.
• Land developers & real-estate due diligence teams siting anything from a single pad site to a subdivision.
• AI agents / MCP tool chains doing automated site-diligence workflows — chain this with the portfolio's landslide, seismic, and levee screeners for a full geohazard sweep from one set of coordinates.

Example input

{
  "assets": [
    { "lat": 28.54, "lon": -81.38, "label": "Orlando, FL" },
    { "lat": 37.5, "lon": -85.6, "label": "Mammoth Cave region, KY" },
    { "lat": 32.0, "lon": -104.0, "label": "Delaware Basin, TX/NM" },
    { "lat": 39.7392, "lon": -104.9903, "label": "Denver, CO (buried evaporite basin)" },
    { "lat": 44.5, "lon": -113.5, "label": "Craters of the Moon area, ID" }
  ],
  "radiusMiles": 2,
  "maxAssets": 500
}

Output fields (one row per asset)

Field	Meaning
asset_label, asset_lat, asset_lon	Echo of the input site.
in_karst_terrain	TRUE if the exact coordinate falls inside a mapped karst/pseudokarst polygon (authoritative point-in-polygon test).
primary_karst_class / primary_karst_label	The highest-severity matched layer (carbonate/evaporite karst rank above sandstone karst, which ranks above subsurface basins, extents, and pseudokarst).
near_surface	TRUE = soluble rock at/near the land surface (the classic active-dissolution condition). FALSE = buried under insoluble cover. Null when not applicable or no hit.
karst_type_detail	The raw USGS description decoded for the primary hit (rock type, depth-of-burial, climate; or basin/lithology for subsurface layers).
rock_unit, mapped_state	Named formation and state, where the source data carries them.
layers_matched, layers_matched_count	Every karst/pseudokarst layer that hits at this exact coordinate (units can overlap).
pseudokarst_flag	TRUE if the hit is soil-piping or lava-tube pseudokarst rather than true soluble-rock karst.
nearby_karst_within_radius, nearby_karst_types	When the exact point is clear, whether mapped karst falls within radiusMiles — catches near-boundary sites given how coarsely national karst polygons are drawn.
sinkhole_risk_context	Editorial tier: Elevated (soluble rock at/near surface), Moderate (karst/pseudokarst present but buried, regional, or non-carbonate), None mapped.
geotech_phase1_flag	TRUE when this site should be a karst/sinkhole line item in Phase-I due diligence.
note	Plain-English one-line summary.
disclaimer, source_url, checked_at	Standing caveat, the USGS FeatureServer used, and the run timestamp.
error	Per-asset error (bad coordinate or upstream query failure); null when OK.

Use as an MCP tool

This actor is Pay-Per-Event priced on the automatic Result event, which makes it directly callable by AI agents (Claude, Cursor, etc.) via mcp.apify.com. Field-level output descriptions are written so an agent can reason about sinkhole_risk_context and geotech_phase1_flag without extra prompting — useful as a grounding tool in a larger site-diligence or underwriting agent.

FAQ

Does this predict an actual sinkhole at my address? No. It screens against a national, regional-scale geologic compilation. Use it to triage which sites need a real geotechnical/karst investigation, not as a substitute for one.

Why does Orlando, FL come back "Moderate" instead of "Elevated" when Florida is famous for sinkholes? Because the USGS map classifies much of central Florida's carbonate bedrock as buried under insoluble sediment (cover-collapse country), not exposed at the surface. Buried soluble rock still carries real subsidence risk — it's just a different collapse mechanism (cover-collapse vs. surface dissolution) than bare, near-surface carbonate karst in places like the Kentucky/Missouri karst belt, which this actor scores Elevated.

What counts as "pseudokarst"? Terrain that behaves like karst (collapse-prone voids) but isn't dissolved soluble rock — soil piping in non-carbonate sediments, and lava tubes in volcanic terrain. Flagged separately via pseudokarst_flag.

Does this cover Alaska or Hawaii? No — the USGS CONUS_Karst compilation is CONUS-only. A non-CONUS coordinate returns a valid None mapped clear row, not an error.

What does a "clear" result cost? Nothing beyond the tiny actor-start — billing is the automatic Result event per pushed row (Pay-Per-Event), so an empty/clear screen doesn't inflate your bill.