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Izmir, the third largest city and one of the major economic centers in Turkey, has more than three million residents and one-half million buildings. The city, located in a seismically active region in western Anatolia, was a subject of the 1997 RADIUS (Risk Assessment Tools for Diagnosis of Urban Areas against Seismic Disaster) project. In this paper, the seismic hazard of Izmir is investigated through probabilistic seismic hazard assessment. First, the seismic setting of Izmir is presented. Considering the statistics of earthquakes that took place in the region during the period 1900-2005, a simple seismic hazard model is used to facilitate the assessment. To account for modeling uncertainties associated with the values of seismicity parameters, a logic tree procedure is employed in carrying out the seismic hazard computations. The resulting weighted average seismic hazard, presented in terms of peak ground acceleration and associated probability of exceedence, could be considered the 'best estimate' of seismic hazard for Izmir. Accordingly, for a return period of 475 years, for rock sites, a PGA value of 0.34 g is calculated. This PGA hazard estimate is close to the current code-recommended design acceleration level for Izmir. [ABSTRACT FROM AUTHOR]

Sivas city, located in the inner east part of Anatolia (Turkey), is far from seismic sources. However, the city is under risk owing to strong earthquakes occurring around the area, and different soil conditions that can produce variation in the ground motion amplification. Microzonation of cities provides a basis for site-specific hazard analysis in urban settlements. In particular, seismic microzonation can be achieved by means of detailed seismic assessment of the area, including earthquake recordings and geological studies. In this paper, we propose a preliminary microzonation map for the city of Sivas, based on the variation in the dominant periods of the sediments covering the area. The periods are retrieved from microtremor measurements conducted at 114 sites, using the horizontal-to-vertical spectral ratio technique. The results of microtremor analysis were compared with those obtained from refraction microtremor measurements at two profiles crossing the studied area. According to the classification of dominant periods, Sivas area can be divided into four zones, probably prone to different levels of seismic hazard. However, specific studies including analysis of weak earthquakes are required in the future to validate our microzonation map. [ABSTRACT FROM AUTHOR]

Earthquake-induced slope instability is one of the major sources of earthquake hazards in near fault regions. Simplified tools such as Newmark's sliding block (NSB) analysis are widely used to estimate the sliding displacement of slopes during earthquake shaking. Additionally, empirical models for predicting NSB displacement using single or multiple ground motion intensity measures based on global (e.g. NGA-W1 database, Chiou et al. 2008) or regional datasets are available. The objective of this study is to evaluate the compatibility of candidate NSB displacement prediction models for the probabilistic seismic hazard assessment (PSHA) applications in Turkey using a comprehensive dataset of ground motions recorded during the earthquakes occurred in Turkey. Then, application of the most suitable NSB displacement prediction model in the vector-valued PSHA framework is demonstrated using the seismic source characterization models developed for Bolu-Gerede Region (in northwest Turkey). The results are presented in terms of the NSB displacement hazard curves and the hazard curves are evaluated for the influence of parameter selection (site conditions, yield acceleration, distance to the fault plane, and other seismic source model parameters) on the final hazard output. [ABSTRACT FROM AUTHOR]