Comparative PGA-driven probabilistic seismic hazard assessment (PSHA) of Turkey with a Bayesian perspective

• Published in: Journal of seismology Vol. 24; no. 6; pp. 1109 - 1129
• Main Authors: Nas, Murat, Lyubushin, Alexey, Softa, Mustafa, Bayrak, Yusuf
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.12.2020; Springer Nature B.V
• Subjects: Bayesian analysis; City centres; Earth and Environmental Science; Earth Sciences; Earthquakes; Estimates; Fault zones; Geological faults; Geological hazards; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Hazard assessment; Hydrogeology; Original Article; Probability theory; Seismic activity; Seismic analysis; Seismic hazard; Seismic zones; Seismicity; Seismology; Structural Geology; Turkey; Bayesian estimation; Seismicity of Turkey; Peak ground acceleration (PGA); Probabilistic seismic hazard analysis (PSHA); Posteriori probability
• ISSN: 1383-4649; 1573-157X
• DOI: 10.1007/s10950-020-09940-5

While there has been significant research on probabilistic seismic hazard analysis (PSHA) using several different seismic sources, this paper focuses particularly on understanding the spatially varying seismic hazard controlled only by earthquakes. In that vein, regarding Turkish seismicity, this study is the first of its kind to explore this conundrum from a Bayesian point of view and offer new estimates to compare with the existing ones. In this study, a national-extent peak ground acceleration (PGA)–driven hazard map (upon 90% quantile of maxima, V S30  = 760 m/s, and a return period of 475 years) was created and then compared both with the old and new versions of the officially recognized seismic hazard maps of Turkey. Regarding 10 earthquake-prone cities, the new PGA estimates were compared with those picked from these two maps. Next, individual site-based hazard estimates were drawn for these city centers considering the return periods of 43, 72, 140, and 475 years. The present hazard map was in compliance with the seismotectonic setup of Turkey and its PGA estimates were slightly high compared with the last two hazard maps for some specific regions, most of which are located in major active fault zones with a history of intense seismic activity, albeit the figures for low seismic zones were relatively low. With this study, it becomes clear that the process of PSHA, which innately requires a long and tiresome effort, can instantaneously be performed against the changing of catalog data over time, and thence prompt evaluations on variations can consequently be made.