Recent movement pattern of the Lower Rhine Embayment from tilt, gravity and GPS data

Abstract

As part of the activities of the Collaborative Research Centre 'SFB 350', measurements of geodetic and geodynamic changes in the area of the Lower Rhine Embayment and the Rhenish Shield are being performed at different scales in space and time. Continuous borehole tilt measurements and repeated microgravimetric surveys yield information on the local stability of the ground and changes in horizontal gravity gradients that are both dominated by seasonal fluctuations. Results of more than seven years of regular GPS campaigns are discussed in terms of vertical and horizontal point motions. The most prominent motions are man-induced effects occurring in or near the browncoal mining areas, where groundwater withdrawal produces subsidence of up to 2.2 cm/y in the area under investigation. Horizontal and vertical motions at other GPS points are smaller by one order of magnitude and in most cases are only marginally detectable. The eastward motion of two points in the Bergisches Land and the westward motion of two points in the Eifel near the Belgian border may be interpreted as a result of the ongoing extension of the Cenozoic rift system in the western part of the Eurasian plate.

GPS monitoring of vertical ground motion in northern Ardenne–Eifel: five campaigns (1999–2003) of the HARD project

“…The maximum difference in height between the sites is 438 m. At the HARD GPS sites, the antenna supports have been anchored in the roof's concrete cornice of flattopped buildings more than 20 years old, so that problems of monument instability are minimized and visibility is excellent down to 10°elevation at least. Moreover, we use the permanent GPS station of the Royal Observatory of Belgium at Membach and two sites of the HEIKO project in western Eifel (Go¨rres and Campbell 1998;Campbell et al 2002).…”

Towards a balanced 3D kinematic model of a faulted domain - the Bergheim open pit mine, Lower Rhine Basin

“…Observations at the exposed normal fault systems (Dethloff, 1993;Seidemann, 1993) document a relatively simple extensional regime, whereby a slight transtensional component (Plein et al, 1982;Klostermann, 1983;Schreiber & Rotsch, 1998) cannot be excluded. GPS-measurements of the recent tectonic movements in the Lower Rhine Basin (Campbell & al., 2002) indicate a horizontal extension in general east-west direction of up to 2 mm/a. Vertical subsidence amounts to at least 2 mm/a, as can be concluded from an earlier geodetic survey before groundwater drawdown due to mine water drainage (Quitzow &Vahlensieck, 1955).…”

Poroelasticity: Finite element modelling of anomalous tilt and pore pressure caused by pumping in a sedimentary half space with fault

“…Consequently, there is the demand for advanced but easy-to-implement models which, (a) describe the influence of anomalies like faults on the surface deformation field, (b) provide a higher spatial resolution for the complete model domain in order to include prominent subsoil structures and (c) can be set up and computed with a manageable effort, preferably in-situ and on a laptop. Particularly for experimental studies in regions with wellconstrained geological settings such as the sedimentary basin of the Lower Rhine Embayment (Campbell et al, 2002;Schäfer et al, 2005) or in areas where intensive geophysical site-surveys were done, such models would allow better placement of tiltmeters, where minima, maxima or any type of prominent signal anomaly of an expected deformation field will occur.…”