ABSTRACT
Located in the Alps, Switzerland is a “hazard-prone” country with 41,300 km2 which are exposed to natural hazards, such as earthquakes, floods, forest fires, snow avalanches, rockfalls and debris flows. Many slopes around the country are affected by small movements related mainly to post-glacial landslide mechanisms and progressive rock slope failure. More than 6% of the Swiss territory is prone to slope instability. Land-use planning and associated zoning laws are among the most effective tools for the prevention and mitigation of natural disasters. New federal regulations require regional authorities to generate natural hazard maps to restrict development on hazard-prone land. A three-step procedure has been proposed. Firstly an indispensable prerequisite for the hazard identification step is to obtain information about past slope failure events. Some recommendations have been developed to allow maps of phenomena to be produced. In the second step, hazard assessment of magnitude or intensity of slope movements over time is determined. The third step defines the risk management. A general acceptable risk considers events with a return period of more than 300 years.
