USGS Karst Sinkhole Risk Screener — Geohazard by Coordinate
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from $4.40 / 1,000 results
Karst & sinkhole-risk screener: batch point-in-polygon over the USGS national CONUS_Karst compilation (7 layers: carbonate, evaporite, sandstone karst + pseudokarst). Returns in_karst_terrain, karst type, near-surface vs buried, rock unit, and an editorial sinkhole-risk tier per coordinate.
Pricing
from $4.40 / 1,000 results
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Developer
Kyle Maloney
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1
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8 days ago
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Asset label
asset_label
Optional
Caller-supplied label for the screened site.
Asset latitude
asset_lat
Optional
WGS84 latitude of the screened site.
Asset longitude
asset_lon
Optional
WGS84 longitude of the screened site.
Search radius (mi)
radius_miles
Optional
Radius used for the nearby-karst check when the exact coordinate is clear.
In karst terrain
in_karst_terrain
Optional
TRUE if the coordinate falls inside one or more mapped USGS karst/pseudokarst polygons (authoritative point-in-polygon test). Null on error rows.
Primary karst class
primary_karst_class
Optional
Machine key of the highest-severity matched layer: carbonate, evaporite, sandstone_karst, evaporite_basin, gypsum_extent, piping_pseudokarst, or volcanic_pseudokarst.
Primary karst label
primary_karst_label
Optional
Human-readable name of the highest-severity matched karst/pseudokarst layer.
Near surface
near_surface
Optional
TRUE if the primary matched unit is mapped at or near the land surface (highest susceptibility); FALSE if buried beneath insoluble cover; null when not applicable (e.g. subsurface basin/extent layers) or no hit.
Karst type detail
karst_type_detail
Optional
Raw decoded USGS description for the primary hit (KARST_TYPE text, DESCRIPT, or basin/lithology summary).
Rock unit
rock_unit
Optional
Named geologic unit or formation for the primary hit, where mapped.
Mapped state
mapped_state
Optional
US state abbreviation carried by the primary hit's source polygon, where available.
Layers matched
layers_matched
Optional
Semicolon-separated list of every karst/pseudokarst layer whose polygon contains this exact coordinate (can be more than one where units overlap).
Layers matched count
layers_matched_count
Optional
Count of distinct karst/pseudokarst layers hit at this coordinate.
Pseudokarst flag
pseudokarst_flag
Optional
TRUE if a hit came from a pseudokarst layer (soil-piping or volcanic lava-tube terrain) rather than true soluble-rock karst.
Nearby karst within radius
nearby_karst_within_radius
Optional
TRUE if the exact coordinate is clear but a mapped karst/pseudokarst polygon falls within the search radius (near-boundary flag). Always false when in_karst_terrain is true.
Nearby karst types
nearby_karst_types
Optional
Semicolon-separated labels of karst layers found within the search radius when the exact coordinate itself is clear.
Sinkhole risk context
sinkhole_risk_context
Optional
Editorial susceptibility tier: 'Elevated' (soluble rock at/near the surface — the classic active-dissolution condition), 'Moderate' (karst or pseudokarst present but buried, regional, or non-carbonate), or 'None mapped'. Null on error rows.
Geotech Phase-I flag
geotech_phase1_flag
Optional
TRUE if this site should be flagged as a karst/sinkhole line item in a Phase-I geotechnical or environmental due-diligence review. Mirrors in_karst_terrain.
Note
note
Optional
Plain-English summary of the result for this asset.
Error
error
Optional
Per-asset error message (invalid coordinate or query failure); null when OK.
Disclaimer
disclaimer
Optional
Susceptibility-screen / not-a-site-specific-prediction note.
Source URL
source_url
Optional
USGS CONUS_Karst FeatureServer used.
Checked at
checked_at
Optional
ISO 8601 timestamp of the run.
Carbonate layer status
carbonate_status
Optional
Outcome of the Carbonates48 carbonate-karst layer query for this coordinate: "ok" = the layer answered, "unavailable" = the query failed (so any negative karst answer on this row is null, not false), "not_checked" = the screen never got that far.
Evaporite layer status
evaporite_status
Optional
Outcome of the Evaporites48 evaporite-karst layer query for this coordinate: "ok" = the layer answered, "unavailable" = the query failed (so any negative karst answer on this row is null, not false), "not_checked" = the screen never got that far.
Sandstone-karst layer status
sandstone_karst_status
Optional
Outcome of the SandstoneKarst48 layer query for this coordinate: "ok" = the layer answered, "unavailable" = the query failed (so any negative karst answer on this row is null, not false), "not_checked" = the screen never got that far.
Evaporite-basin layer status
evaporite_basin_status
Optional
Outcome of the EvapBasins subsurface evaporite-basin layer query for this coordinate: "ok" = the layer answered, "unavailable" = the query failed (so any negative karst answer on this row is null, not false), "not_checked" = the screen never got that far.
Gypsum-extent layer status
gypsum_extent_status
Optional
Outcome of the GypsumExtent broad indicator layer query for this coordinate: "ok" = the layer answered, "unavailable" = the query failed (so any negative karst answer on this row is null, not false), "not_checked" = the screen never got that far.
Soil-piping layer status
piping_pseudokarst_status
Optional
Outcome of the Piping48 soil-piping pseudokarst layer query for this coordinate: "ok" = the layer answered, "unavailable" = the query failed (so any negative karst answer on this row is null, not false), "not_checked" = the screen never got that far.
Volcanic-pseudokarst layer status
volcanic_pseudokarst_status
Optional
Outcome of the Volcanics48 lava-tube pseudokarst layer query for this coordinate: "ok" = the layer answered, "unavailable" = the query failed (so any negative karst answer on this row is null, not false), "not_checked" = the screen never got that far.
Screen status
screen_status
Optional
Overall point-in-polygon screen outcome: "complete" (all 7 layers answered), "partial" (some answered -- a negative result is then reported as null, never as "no karst"), or "failed" (none answered, or the coordinate was invalid).
Screen complete
screen_complete
Optional
TRUE only when all 7 USGS karst layers answered for this coordinate. When FALSE, treat every null karst field as "not checked" rather than "no karst".
Layers screened (total)
layers_screened_count
Optional
How many USGS CONUS_Karst layers this actor screens (7 -- layer 0 is a glacial-extent polyline and is excluded).
Layers that answered
layers_screened_ok_count
Optional
How many of the 7 karst layers actually returned a result for this coordinate.
Result truncated
result_truncated
Optional
TRUE if an ArcGIS page still flagged exceededTransferLimit after the actor had walked its pagination limit, meaning the feature list on this row may be incomplete. Normally false.
Nearby screen status
nearby_screen_status
Optional
Outcome of the radius search: "complete", "partial", "failed", "not_applicable" (the coordinate is already inside mapped karst so no radius search was needed), or "not_checked".
Nearest karst (upper bound, mi)
nearest_karst_bound_miles
Optional
An honest UPPER BOUND, in miles, on the distance to the nearest mapped karst polygon, found by halving the search radius while something still intersects. Populated only when the exact coordinate is clear but karst was found within the radius. A bound, not a measured distance.
Primary feature ID
primary_feature_id
Optional
USGS FID of the specific polygon that drove the verdict, so the exact source record can be re-queried.
USGS Exposure code
exposure_code
Optional
Authoritative USGS Exposure code on the primary hit: E (exposed at/near the surface), B1 (buried under less than 300 ft of insoluble sediments), B2 (buried under more than 50 ft of glacial cover), B3 (buried under 50 ft or less of glacial cover). The letters are NOT a depth ranking -- B3 is shallower than B1. Null on layers that do not carry it.
Exposure description
exposure_description
Optional
Plain-English decode of exposure_code.
Overburden description
overburden_description
Optional
The insoluble cover described by the USGS record, e.g. "Buried under <300 ft of insoluble sediments" -- what a foundation designer needs beyond the near_surface boolean.
Induration
induration
Optional
USGS Induration of the primary unit: Consolidated or Unconsolidated. Unconsolidated calcareous sediment behaves very differently from consolidated limestone.
Climate regime
climate
Optional
USGS climate regime for the primary hit, dry or humid -- a control on dissolution rate. Reported verbatim from the source, which occasionally disagrees with local expectation.
Rock types
rock_types
Optional
ROCKTYPE1-3 from the primary hit, comma separated.
Lithology class
lithology_class
Optional
Coarse lithology of the primary hit: carbonate, evaporite, sandstone, volcanic, or a mixed combination. Evaporite (gypsum/halite) dissolves orders of magnitude faster than carbonate.
Unit age
unit_age
Optional
Geologic age of the primary mapped unit.
Unit link key
unit_link
Optional
USGS SGMC unit key for the primary hit.
Unit source URL
unit_source_url
Optional
USGS mrdata page for the primary mapped unit.
EPA Level-III ecoregion
ecoregion_l3
Optional
EPA Level-III ecoregion name carried by the primary polygon.
Unit comments
unit_comments
Optional
USGS free-text COMMENTS on the primary polygon. Sparse (about 1.4% of records) but valuable when present -- it often names the karst feature itself, e.g. "Carlsbad Caverns" or "Lava Beds National Monument".
Evaporite basin name
evaporite_basin_name
Optional
Named subsurface evaporite basin containing this coordinate, when the EvapBasins layer matched.
Evaporite formation
evaporite_formation
Optional
Named evaporite-bearing formation in that basin.
Evaporite formation age
evaporite_formation_age
Optional
Geologic age of the evaporite formation.
Evaporite depth range
evaporite_depth_range
Optional
Depth range to the evaporite formation as published by USGS, e.g. "0-700 m" -- the single most useful number for judging deep-dissolution subsidence risk.
Evaporite thickness
evaporite_thickness
Optional
Published thickness of the evaporite formation, e.g. "300-600 m".
Evaporite lithology
evaporite_lithology
Optional
Evaporite minerals present, e.g. "halite, anhydrite, gypsum".
All karst classes
all_karst_classes
Optional
Semicolon-separated machine keys of every karst/pseudokarst class matched at this exact coordinate -- the filterable companion to layers_matched.
Risk basis (audit trail)
risk_basis
Optional
Which layer drove the verdict and on what evidence -- layer id, USGS FID, whether it is a mapped unit or a broad regional indicator, the Exposure code and the unit name, for every contributing layer.
Karst mechanism
karst_mechanism
Optional
The physical process implied: surface_dissolution, cover_collapse, deep_evaporite_dissolution_subsidence, soil_piping, lava_tube_collapse, or broad_regional_evaporite_indicator.
Broad indicator only
broad_indicator_only
Optional
TRUE when the ONLY basis for in_karst_terrain is a broad regional layer (the single nationwide GypsumExtent polygon or a basin-scale EvapBasins polygon) rather than a mapped karst unit at this coordinate. Roughly a third of the lower 48 falls inside GypsumExtent, so this flag separates a real karst hit from the regional blanket. Null when the screen was incomplete.
Soluble-rock karst flag
soluble_rock_karst_flag
Optional
TRUE when at least one TRUE soluble-rock karst layer (carbonate, evaporite or sandstone karst) matched, as opposed to only pseudokarst or a broad indicator. Null when the screen was incomplete.
Karst confidence
karst_confidence
Optional
How precisely the driving layer locates the hazard: "low" for the nationwide gypsum extent and basin-scale evaporite polygons, "moderate" for a mapped geologic unit at formation scale. Never "high" -- this is a regional screen.
Data vintage
data_vintage
Optional
The USGS publication behind the compilation and its update posture.
