EARTHQUAKE RISK MITIGATION IN SWITZERLAND - SUCCESSES, FAILURES AND CHALLENGES IN A COUNTRY OF MODERATE SEISMICITY

摘要

Switzerland is a small country located in a zone of moderate seismicity in central Europe. It is a federal state with 26 cantons (states) that have a large legislative autonomy in many fields such as construction or education. For the mitigation of most natural hazards on the other hand, the federal authority has a strong legislative competence given by the Constitution. This means it can develop risk mitigation strategies that have to be implemented by the cantons with the help of federal subsidies. This way of doing should insure nationwide protection standards against natural hazards.Earthquake risk mitigation being a very recent issue in Switzerland, it is not dealt with in the Swiss constitution. Therefore, the federal authority has only limited prerogatives to act in this domain and the responsibility for earthquake risk mitigation is mainly left to the cantons. With this situation, there is a risk to see 26 different solutions being developed by the 26 different cantons. This would mean very different seismic protection standards for the population and the goods across a small nation with only 7.7 million inhabitants. To try to alleviate this potential problem, a constitutional change was proposed in 2003, but refused by a commission of the national parliament.This paper presents an overview of seismic risk mitigation in Switzerland and discusses the main successes and failures since the starting point of risk mitigation initiatives in Switzerland in the mid-1990s. Difficulties induced by the combination of a federal political system with a strong regional autonomy and the general low awareness due to the low recurrence rate of damaging events are discussed. Actual major challenges and the solutions that are foreseen to effectively reduce the seismic risk in the long term are finally outlined.