High resolution 3D laser scanner measurements of a strike‐slip fault quantify its morphological anisotropy at all scales

The surface roughness of a recently exhumed strike‐slip fault plane has been measured by three independent 3D portable laser scanners. Digital elevation models of several fault surface areas, from 1 m 2 to 600 m 2 , have been measured at a resolution ranging from 5 mm to 80 mm. Out of plane height fluctuations are described by non‐Gaussian distribution with exponential long range tails. Statistical scaling analyses show that the striated fault surface exhibits self‐affine scaling invariance with a small but significant directional morphological anisotropy that can be described by two scaling roughness exponents, H 1 = 0.7 in the direction of slip and H 2 = 0.8 perpendicular to the direction of slip.