It is thought that because the collision was irregular, the initial contact between the two continents resulted in the formation of dilational (extensional) structures in the foreland basin to the north of the Alps.The northern section of the Rhine Plain is equally framed by somewhat lower mountain ranges, the Palatinate Forest on the western and the Odenwald on the eastern side.The extension induced by the formation of the Alps was sufficient to thin the crust and provide suitable dilational conduits for magmatic and volcanic activity to occur.Doubts have been raised over the adequacy of the seismic evaluation and design of the Fessenheim Nuclear Power Plant, built in the Rhine Plain close to the faults.[7] [8] A collaboration of 25 universities and government agencies have been researching seismic hazards, neotectonics, and water management of the Quaternary Graben fill.
Schematic cross-section of the Rhine Rift Valley.
Rhine Graben (blue shades) between Basel and Frankfurt with adjoining mountain ranges (green to brown); colour-coding according to digital elevation model
A satellite view of the plain: Shot taken by
NASA
satellite