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What causes sinkholes and karst subsidence in Oklahoma?

Reviewed by Preston, Oklahoma foundation repair consultant ยท Updated 2026-10-14

In short: Karst is ground shaped by rock that dissolves in water, such as gypsum, salt, limestone and dolomite. As groundwater dissolves the rock, cavities form, and the soil above can slowly sag into them or collapse suddenly as a sinkhole. In Oklahoma, gypsum and salt karst is found in the west, and limestone and dolomite karst in the northeast and south.

How do karst sinkholes form?

Sinkholes form where groundwater moving through soluble rock dissolves it and creates underground cavities 1. The ground above may hold for a time, then fail when a cavity grows too large to support it 1. The rock types involved are evaporites (salt, gypsum and anhydrite) and carbonates (limestone and dolomite) 1.

The USGS describes three main types 1:

Type How it develops
Dissolution Rock dissolves where water first reaches it, forming a gradual depression
Cover-subsidence Sandy, permeable cover soil gradually sifts down into openings
Cover-collapse Clay-rich cover bridges a growing cavity, then fails abruptly, sometimes within hours

Natural triggers include rainfall soaking through rock, changes in the water table and surface drainage concentrating in low spots 1. Human changes to drainage, groundwater pumping and heavy new loads can also contribute 1. The Oklahoma Geological Survey adds that karst sinkholes can form when floodwater rises to a cavern's ceiling and then recedes 7.

Where is karst found in Oklahoma?

Rock type Main Oklahoma areas
Gypsum and shallow salt Many areas of western Oklahoma 34
Limestone and dolomite Ozark region (northeast), Arbuckle Mountains (south) and Limestone Hills 34

Western gypsum

Gypsum beds of Permian age crop out in parts of 15 Oklahoma counties 5. The thickest gypsum is in the southwest, mainly across about 600 square miles in Beckham, Greer and Jackson Counties, where the Blaine Formation is about 200 feet thick, about 150 feet of it massive gypsum 5. Near Watonga in northwestern Oklahoma, Blaine gypsum beds lie about 40 to 140 feet below the surface 6.

Gypsum is highly soluble and forms karst features much like limestone does; gypsum karst in the U.S. has been linked to highway subsidence, dam failure and foundation cracking 6. An Oklahoma Geological Survey circular notes that evaporite karst can damage or collapse homes, buildings, roads and dams 2. See gypsum karst and sinkholes, Permian gypsum units and the Northwest (Gypsum Hills) region.

Eastern and southern limestone

In the Ozark region and the Arbuckle Mountains, karst forms in limestone and dolomite 3. See Arbuckle carbonates and Mississippian cherty limestone.

What are the signs of karst subsidence?

Sinkholes and caverns can cause land to settle or collapse 3.

How does karst differ from shallow erosion voids?

Not every sinkhole is karst. The OGS notes that most of the sinkholes expected after Oklahoma's heavy April 2025 rains were small ones where water flowed beneath roads and driveways, eroding soil rather than dissolving bedrock 7. Karst sinkholes are controlled by soluble bedrock and range from under 1 foot to more than 100 feet deep 1. See erosion, undermining and washout voids.

How is karst evaluated?

In a 2010 study of gypsum karst risk in northwestern Oklahoma, geologists recommended gathering subsurface data from petroleum test records and core borings and surveying local landowners about past sinkholes or collapses 6. They judged gypsum 80 feet or deeper to be low risk and shallower gypsum to be medium or high risk 6. The OGS is building a statewide subsidence map and accepts sinkhole reports from the public 7.

Repair options for void-related settlement discussed on this site include void and compaction grouting.

Free, plain-English answers. It asks a few questions and walks you to the repair that fits.

Common questions

What causes sinkholes in Oklahoma?

Karst sinkholes form where groundwater dissolves soluble rock such as gypsum, salt, limestone or dolomite, creating cavities that the ground above eventually settles or collapses into. Smaller sinkholes can also form when flowing water erodes soil beneath roads and driveways.

Where is gypsum karst found in Oklahoma?

Gypsum and shallow salt deposits occur in many areas of western Oklahoma. The thickest gypsum is in the southwest, mainly across about 600 square miles in Beckham, Greer and Jackson Counties, where the Blaine Formation contains up to about 150 feet of massive gypsum.

Where is limestone karst found in Oklahoma?

Limestone and dolomite karst occurs mainly in the Ozark region of northeastern Oklahoma and the Arbuckle Mountains of southern Oklahoma, with karst also noted in the Limestone Hills.

Can gypsum karst crack a foundation?

Yes. Geologists have linked gypsum karst in the United States to highway subsidence, dam failure and foundation cracking, and the Oklahoma Geological Survey notes that evaporite karst can damage or collapse homes and buildings.

How do I report a sinkhole in Oklahoma?

The Oklahoma Geological Survey accepts sinkhole reports through an online survey as part of its work on a statewide subsidence map.

Sources

  1. Sinkholes U.S. Geological Survey Water Science School
  2. Evaporite Karst and Engineering/Environmental Problems in the United States (Circular 109) Oklahoma Geological Survey
  3. Mapping of Karst Terranes in Oklahoma to Identify Potential Environmental and Hydrologic Problems AAPG Search and Discovery (K. S. Johnson, Oklahoma Geological Survey)
  4. Geologic Hazards in Oklahoma Geological Society of America (abstract by K. V. Luza, Oklahoma Geological Survey)
  5. Stratigraphy of the Blaine Formation in Beckham County, Oklahoma Proceedings of the Oklahoma Academy of Science
  6. Gypsum Karst and Potential Problems in Siting Wind Turbines in Northwest Oklahoma Geological Society of America (Abstracts with Programs, 2010)
  7. Hazard Mapping Oklahoma Geological Survey, University of Oklahoma

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