Abstract
Distribution and features of incised valleys and buried terraces in the Yodo River lowland, the Osaka Plain, Japan were reconstructed using a borehole database. Two gorges were discovered in the incised valley of the paleo Yodo River. The width of the incised valley was large in the lower reach of the river due to the effect of wave erosion. The buried terraces distributed intermittently along the paleo Yodo River were interpreted as river terraces based on their distribution and morphology. The River bed gradient of the paleo-Yodo River changed in the two gorges. The gradient in the upper reach of the gorge is gentle, whereas the lower reach is steep. This is ascribable to tectonic movement to form gorges and sedimentation and lateral erosion there. The older upper terraces have gentler gradients converge with the paleo Yodo River bed in the upper reach. The effect of river bed degradation associated with sea level fall seems to have progressed upstream.
