Influence of seismic source and ground motion modeling on the probabilistic seismic hazard assessment of the city of Van after the 23 october 2011 mw7.2 earthquake

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2013
Şenyurt, Mehtap
Reliable assessment of seismic hazard is the most important step for seismic design and performance assessment of structural systems. However, the inherent uncertainty in earthquakes as well as modeling of ground motion may affect the hazard computed for a particular region. This study investigates the influence of seismic source and ground motion modeling on probabilistic seismic hazard assessment (PSHA). The study considers the seismicity around the city of Van to achieve its objective as this city was hit by a major earthquake on 23 October 2011 (Mw 7.2) that was followed by another significant event on 9 November 2011 (Mw 5.6). These two earthquakes caused loss of a substantial number of lives and left many locals homeless with a huge socio-economic impact. They re-emphasized the importance of seismic induced hazard in the region and uncertainties involved both in source and ground-motion variability to quantify hazard in the region. The importance of each input parameter in PSHA is depicted by studying the uncertainties that are ranked through sensitivity analysis. A multi-parameter approach that is proposed by Rabinowitz and Steinberg (1991) is utilized in sensitivity analysis. The method not only indicates the individual effects of each input parameter but also portrays the interaction between the input PSHA parameters. The study accounts for the uncertainty in PSHA by considering the variations in the estimation of ground motion intensity measure, the level of standard deviation, earthquake catalog information, selection of recurrence models, selection of maximum magnitude and slip rate of the faults in the region of interest. The individual effects of these parameters and their mutual interactions are examined by using the aforementioned multi-parameter sensitivity approach. The calculations are done for peak ground acceleration (PGA) as well as pseudo-spectral acceleration (PSA) ordinates at T = 0.2s and T = 1.0s (i.e., PSA(T=0.2s) and PSA(T=1.0s)). The return periods chosen for the sensitivity analyses are 72, 475 and 2475 years that are used by the Turkish Earthquake Code (TEC, 2007) for seismic design and performance assessment of building structures. The discussions presented in this thesis can be used for deriving the design spectra for the above return periods for future engineering studies in the city of Van and surrounding regions.
Citation Formats
M. Şenyurt, “Influence of seismic source and ground motion modeling on the probabilistic seismic hazard assessment of the city of Van after the 23 october 2011 mw7.2 earthquake,” M.S. - Master of Science, Middle East Technical University, 2013.