Schematic diagram showing models. Where the stress inversion observed in the calcite vein sample CV-2 (338-C0002F-258-SMW) occurs during development of (a) folds and (b) seismic cycles. (a, left) Calcite vein denoted by penny-shaped objects (black) formed by layer-parallel shortening and fluid overpressure in a horizontal layer. (a, right) Two positions of calcite veins at the outer hinge and limb of a fold after the formation of a tight fold. (b, left) Stress state in the upper plate of the megathrust in the Nankai accretionary prism caused by the relief of shear stress and fluid discharge after earthquakes (Sibson, ). (b, right) Stress state during the interseismic period. The stress state before earthquakes is recovered by stress accumulation and an increase in the pore fluid pressure. The open, large arrows with σ1, R and σ3, R denote the orientations of regional maximum and minimum principal stress axes, while the small arrows with σ1, L and σ3, L denote the orientations of local maximum and minimum principal stress axes. The intermediate stress σ2 axis is assumed to be oriented in the horizontal orientation. See text for explanations.