Fracture Gradient

{
  "id": "MLC-T-ENV-011641",
  "term": "Fracture Gradient",
  "field": "Environment",
  "definition": "The fracture gradient is a measure of how the pressure required to fracture rock in the earth changes with depth. It is usually measured in units of \"pounds per square inch per foot\" (psi/ft) and varies with the type of rock and the stress history of the rock. The default value used by Region 5 in Michigan is 0.8 psi/ft. This means, for example, that at a depth of 100 ft, a pressure of 80 psi would be required to fracture the rock, while at a depth of 500 ft, the required pressure would be 400 psi; at 1000 ft, 800 psi. The fracture gradient is used in the calculation of the maximum injection pressure.",
  "subject": "Land, waste and cleanup",
  "references": [
    "Underground Injection Control Terms"
  ],
  "url": "https://mlchart.com/terminology/environment/fracture-gradient/"
}