Land subsidence and hydrodynamic compaction of sedimentary basins

A one-dimensional model is used to investigate the relationship between lan d subsidence and compaction of basin sediments in response to sediment load ing. Analysis of the model equations and numerical experiments demonstrate quasi-linear systems behaviour and show that rates of land subsidence due t o compaction: (i) can attain a significant fraction (>40%) of the long-term sedimentation rate; (ii) are hydrodynamically delayed with respect to sedi ment loading. The delay is controlled by a compaction response time tau c t hat can reach values of 10(5)-10(7) yr for thick shale sequences. Both the behaviour of single sediment layers and multiple-layer systems are analysed . Subsequently the model is applied to the coastal area of the Netherlands to illustrate that lateral variability in compaction-derived land subsidenc e in sedimentary basins largely reflects the spatial variability in both se diment loading and compaction response time. Typical rates of compaction-de rived subsidence predicted by the model are of the order of 0.1 mm/yr but m ay reach values in excess of 1 mm/yr under favourable conditions.