Relevance of tectonic and structural parameters in Triassic bedrock formations to landslide susceptibility in Quaternary hillslope sediments Bodo Damm a, b, * , Michael Becht b , Kinga Varga b , Tobias Heckmann b a University of Regensburg, Institute of Geography, Universitätsstrasse 31, 93053 Regensburg, Germany b Catholic University of Eichstätt-Ingolstadt, Chair of Physical Geography, Ostenstrasse 18, 85072 Eichstätt, Germany article info Article history: Available online 11 March 2010 abstract Important controlling factors of mass movements are generally soil water and geometric-topographic terrain factors such as inclination, curvature type and degree, and the relative position of unstable slopes and embankments. In addition, various geologic parameters that have a direct or indirect connection to soil-mechanical properties of slide masses are also of importance. Some studies also emphasise tectonic parameters in the context of susceptibility to mass movements. This study considers the relevance of tectonic and structural parameters in bedrock formations for landslides in periglacial hillslope sediments on top of the bedrock. The research area is part of the southern Solling anticline, a saddle structure in the Middle Bunter Sandstone formation in northern Hesse and southern Lower Saxony (Germany). In this geologic formation, sandstone, siltstone, and mudstone are interbedded with impermeable strata. Uplift of the Solling anticline, in particular during the Quaternary, resulted in a partially intensive dissection of the Bunter Sandstone plateau into separate blocks with disrupted, tilted, and partially rotated layers. The structural conditions have an indirect impact upon landslides in the superposed hillslope sediments. Water flow along strata and joints above water impermeable strata cause water infiltration and moist- ening of the periglacial hillslope sediments on top of the bedrock. Mass movements are frequently linked to sites of outcrop springs and occur after long periods of rainfall. A GIS-based analysis was used to statistically evaluate possible factors controlling landslides. Factors were weighted and included in an empiric-statistical model that allows spatial description of hazard potentials due to mass movements. In addition to morphologic parameters, the structural parameters of the bedrock are of utmost importance for the occurrence of landslides. Ó 2010 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction Quaternary landscape formation affects present-day geo- morphodynamics. To understand present-day processes and predict future developments, it is essential to understand the past ones. In order to recognise and evaluate factors controlling morphody- namics, historical analysis has significant relevance (Semmel, 1996; Barnikel and Becht, 2005; Dreibrodt et al., 2009; Terhorst et al., 2009). Frequently, in context with the occurrence and type of process factors, Quaternary landscape development has important relevance (Damm and Terhorst, 2009; Terhorst and Kreja, 2009). In connection with climate change and coupled with regionally increasing precipitation rates, the study of landslide hazards in the temperate zone is becoming more pronounced in scientific and public interest. In Germany, mass movements of different types and ages are widespread and the vulnerability of society with respect to slope movements has increased considerably (cf. Becht and Damm, 2004; Damm, 2006). For this reason, knowledge about the distri- bution of vulnerable areas and damage potential is essential for spatial planning and building authorities. Spatial analysis and prediction of landslide hazards are gaining importance. Based on statistical analysis of factors controlling mass move- ments, Geographical Information Systems (GIS) allow effective evaluation and forecasting of hazard-prone sites, recently including a larger amount of information regarding vulnerability, such as location, magnitude, and frequency (among others Thein et al., 1995; Kreikemeier et al., 2004; Guzzetti et al., 2006; Terhorst and Kreja, 2009). The basis to describe the spatial susceptibility to landslides is the identification and evaluation of factors that decrease the stability of soils and unconsolidated rocks (e.g. Terzaghi, 1950; * Corresponding author. University of Regensburg, Institute of Geography, Universitätsstrasse 31, 93053 Regensburg, Germany. Tel.: þ49 9419433605. E-mail address: bodo.damm@ku-eichstaett.de (B. Damm). Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint 1040-6182/$ e see front matter Ó 2010 Elsevier Ltd and INQUA. All rights reserved. doi:10.1016/j.quaint.2010.02.022 Quaternary International 222 (2010) 143e153