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

TL;DR

This study uses high-resolution 3D laser scanning to measure the surface roughness and anisotropy of a strike-slip fault, revealing scale-invariant features and directional morphological differences.

Contribution

It introduces a detailed 3D measurement approach to quantify fault surface anisotropy and scaling properties at multiple scales.

Findings

Fault surface exhibits self-affine scaling invariance.

Directional roughness exponents differ: H1=0.7 along slip, H2=0.8 perpendicular.

Height fluctuations follow non-Gaussian distributions with exponential tails.

Abstract

The surface roughness of a recently exhumed strikeslip fault plane has been measured by three independent 3D portable laser scanners. Digital elevation models of several fault surface areas, from 1 m2 to 600 m2, 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, H1 = 0.7 in the direction of slip and H2 = 0.8 perpendicular to the direction of slip.