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Effects of Inputs on PSHA Results: A Case Study Hydropower Cascade Projects in Georgia (Sakartvelo)

Session: Probabilistic Seismic Hazard Assessment: Where Do We Go from Here? [Poster]

Type: Poster

Date: 4/20/2021

Presentation Time: 11:30 AM Pacific

Description: 

Despite many investigation within several regional and global initiatives to harmonize methodology for probabilistic seismic hazard assessment (PSHA) there are still big incompatibility in PSHA results. That leads to disagreements among experts. In the present work we consider the different results of PSHA obtained by different scientific group for the same critical infrastructure like hydro power plant that is located in the north-western part of Georgia.

Analysis of thy conducted work gave us idea that the main rezone of obtained differences in PSHA results came due to inputs. Uncertainties associated with earthquake location and magnitude , homogenization of the earthquake catalogues in terms of moment magnitude (Mw), model of area seismic sources, selection of GMPE models have a significant influence on seismic hazard assessment. For any seismic hazard assessment study following the classical probabilistic approach established by Cornell (1968) the declustering of the earthquake catalogue compiled for the region has become a standard practice. Meanwhile, some authors used non- declustering catalog , indicating that it does not effects of PSHA results. Though investigation show not only non-declustering catalogue influence on PSH results, but also the methods of declustering can influence on them and should be considered in PSHA.

Another important input that effects on PSHA is model of area seismic sources (ASS). Not always authors follow the main criteria that were developed in global project GEM. Free interpretation of area sources leads to different results of PSHA as their size effects very much on seismic productivity. Influence of GMPE models also is significant but if the main criteria of GMPE selection procedure is followed it reduce their effects on PSHA results.

Finally methodology of PSHA also has effects on seismic hazard assessment results. Avoiding such misunderstand it is essential following international standards that were developed recently by the global project GEM or established a new recommendations.

Presenting Author: Nino S. Tsereteli

Student Presenter: No

Authors