Fig. 3

Reduced χ² distributions obtained by grid search for (a) 1.5-yr and (b) 2.2-yr data. The vertical and horizontal axes indicate the viscosity of the viscoelastic layer and the elastic thickness, respectively. The small circles indicate calculated points. The grey scale represents a reduced χ² value. The dashed contour line indicates the confidence limit of 1-σ. For comparison, the same dashed contour line of (a) is plotted in (b) in white.