A contour plot showing how small perturbations in the modelled thickness and seismic velocity of the LVZ found on Line 3, effects the χ² and rms error of the final Jive3D model. Thickness perturbations of ±.0, 0.1, 0.25, 0.5 and 0.75 km were tested in conjunction with velocity perturbations of ±0.05, 0.1, 0.15 and 0.2 km s⁻¹, and each model run is represented by a circle. The contour plot on the left indicates the effect on χ². while the contour plot on the right indicates the effect on rms error.