Quantitative rockfall hazard and risk analysis in selected municipalities of the České Švýcarsko National Park, northwestern Czechia

Abstract

Quantitative rockfall hazard and specific risk assessment of the selected municipalities within the České Švýcarsko National Park was performed using two rockfall hazard analysis modelling codes. CONEFALL and RockFall Analyst codes were used to delimit rockfall hazard regions. Specific risk to buildings was consequently assessed using results from the hazard analysis and literature-derived vulnerability values. Results of hazard and risk assessments for two nearby municipalities were compared and evaluated. Both models provide similar rockfall hazard values in areas characterized with relatively steep (36°–50°), convex and short slopes (up to 200 m). Whereas in regions with less steep (20°–35°), concave and longer slopes (about 350 m) the predicted rockfall hazard differs considerably. We argue that the results of the RockFall Analyst are more reliable due to complex input data and modelling approach which closely resembles the natural process of falling rocks on forested slopes. Differences in hazard assessment are further reflected in assigning risk values to exposed buildings, where CONEFALL is more conservative.