Patterns and velocities of recent crustal movements in the Dutch part of the Roer Valley rift system

Abstract

This article presents an integration of geomorphological and geodetic data from the area of the 1992 Roermond earthquake. A dense network of lineaments is evident from major and minor terrain features, and drainage patterns also show structural control on a kilometre scale. These discontinuous terrain lineaments, often of anastomosing character, match known fault patterns and suggest that the upper crust is subdivided into many, relatively small (up to 10 km scale) wedge-shaped blocks. The lineament distribution is consistent with patterns predicted by idealized strain ellipses. It shows a right lateral component in the motion along major faults within the Lower Rhine Embayment. The wrenching component can be related to a left-lateral motion along the Variscan Front, and a subsequent right lateral offset of the edge of the London-Brabant Massif. The analysis of a 117-years-long data set of vertical movements at 2922 geodetic bench-marks evidences significant differential movements, and corroborates the sense of relative motion given by the lineaments.