4th Swiss Geoscience Meeting, Bern 2006 Geomorphic constraints on Quaternary tectonic activity in the Basel area

characterized by the adjoining tectonic units of the Upper Rhine Graben (URG), the Jura fold-and-thrust belt and the Black Forest massif. While the evolution of these partly overlapping and interfering structures is quite well understood on a large timescale (e.g., Dèzes et al. 2004), unanswered questions remain concerning the youngest (Quaternary) development of the region. Seismological data and geodetic measurements show that tectonic deformation has not stopped (Müller et al. 2002). A link between these short-term indications and the longer-term tectonic development is provided by the work of Giamboni et al. (2004), which demonstrates recent compressional deformation in the Ajoie region, at the border between the Jura and the URG. Whether this compression is limited to the Ajoie, or whether it also affects the easternmost part of the Jura, could not be determined so far. Its increased earthquake activity makes the south-eastern corner of the URG a promising place to look for other evidence of tectonic deformation. Moreover, a better understanding of the recent tectonic activity is essential to assess the seismic risk in this densely populated area. Competing hypotheses about the style of deformation (thin-skinned / thick-skinned) further motivate the search for additiona