TABLE 1

Fracture strike and frequency data

Sample nameFracture strike*UK national grid referenceMicrofracturesMacrofractures
GridEastNorthScan line length (mm)N**εabScan line length (mm)N**ε
I90NG995006545027.31010.07223.50.856523530.016
II0NH423269410126.21530.0194.00.842308620.018
III110NH61007137833.6380.0093.50.8530911230.028
IVa30NH77687440648.61040.0152.20.987198480.002
IVb0NH77687440647.4110.0010.21.17
IVc90NH77687440634.8110.03610.80.56
  • * Centre of 50° azimuth window.

  • ** N, number of fractures intersecting scan line within azimuth window; ε strain; a, power law coefficent; b, power law exponent.