Figure 5From: Geotechnical behavior of mudstones from the Shimanto and Boso accretionary complexes, and implications for the Nankai accretionary prismPrinciple for the determination of effective shear parameters from fracture angles. σ1′ = maximum effective stress, σ3′ = minimum effective stress, σ′ = normal stress, φ = friction angle, C = cohesion, τ = shear stress, α = fracture angle. Diagram modified after Richter (1989).Back to article page