Interactive map of seismic hazard for nuclear facilities, Czech Republic

The main aim of this project is create an interactive map of seismic hazard of the territory of the Czech Republic and the system of its upgrading. The map will fulfill the recommendation of the International Atomic Energy Agency for evaluation of seismic hazard at the sites of nuclear facilities. It will serve as the background material during the process of approving of seismic safety of nuclear infrastructure. The interactive map will enable also to improve seismic hazard assessment for non-nuclear buildings, facilities and infrastructure. The system of continual upgrading will enable to include the new scientific results in the field of seismic hazard and experience from new earthquakes. Czech Republic is situated in an intraplate region with low seismicity. The seismic hazard is relatively low, but not negligible. The seismic hazard is evaluated by probabilistic seismic hazard method, including construction of logic tree and deriving of seismic hazard curves. In areas, where no or just a few weak events are recorded, but significant earthquakes can occur from both geological and seismological point of view, the concept of diffused seismicity is applied. Historical catalogs in weak-seismic regions cover a much shorter period than the average time between the strong (controlling) earthquakes. This cause a complicate evaluation of focal zone maximal magnitude parameter. Hence, a new method of maximal magnitude determination was developed. It uses Bayesian approach combining a priori information from wider region with historical earthquake catalogue resulting in probability distribution of maximum magnitude. For the evaluation of the local conditions, the new Vs30 map of Czech Republic is prepared. The map combines method of Wald and Allen (2007), using topographic slope as a proxy for seismic site conditions and amplification, and new Vs30 field measurements on multiple locations in the area of study. References: Wald, J.W. and Allen, T.I (2007): Topographic Slope as a Proxy for Seismic Site Conditions and Amplification, doi: 10.1785/0120060267.