PATTERNS AND VELOCITIES OF RECENT CRUSTAL MOVEMENTS IN THE DUTCH PARTOF THE ROER VALLEY RIFT SYSTEM

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 drai nage patterns also show structural control on a kilometre scale. These discontinuous terrain lineaments, often of anastomosing character, ma tch known fault patterns and suggest that the upper crust is subdivide d into many, relatively small (up to 10 km scale) wedge-shaped blocks. The lineament distribution is consistent with patterns predicted by i dealized strain ellipses. It shows a right-lateral component in the mo tion along major faults within the Lower Rhine Embayment. The wrenchin g component can be related to a left-lateral motion along the Variscan Front, and a subsequent right-lateral offset of the edge of the Londo n-Brabant Massif. The analysis of a 117-years-long data set of vertica l movements at 2922 geodetic bench-marks evidences significant differe ntial movements, and corroborates the sense of relative motion given b y the lineaments.