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We present a dataset of 77 strong ground motion records within 200 km epicentral distance from the 30 October 2020, M7.0 Samos Island (Aegean Sea) earthquake, which affected Greece and Turkey. Accelerograms from National Networks of both countries have been merged into a single dataset, including metadata that have been uniformly derived using a common preliminary source model. Initial findings from the analysis and comparative examination of acceleration time histories, Fourier amplitude spectra and 5%-damped response spectra are discussed along with significant source, propagation path and site effects. The long-period amplifications observed in most records in Izmir bay triggered failures and severe damages in weak structures. Yet, the spectral accelerations are observed to lie below the current and previous design spectra corresponding to the damaged regions. Peak ground motions are used to construct a purely instrumental-based macroseismic intensity map, which is capable of reflecting the actual earthquake damage caused by this considerably large event. Finally, peak ground motions are compared to various ground motion models (GMMs) and deviations are highlighted. Our overall preliminary analysis reveals a strong energy signature of the Samos earthquake in the period range 0.5-1.5 s at many sites, both on rock and soil, whereas records in the heavily hit Izmir city, at an epicentral distance circa 70 km, provide strong indication for additional amplification due to basin effects. At relatively large distance from the earthquake source (> 120 km), several recorded amplitudes are significantly lower than those predicted by many GMMs, implying that further studies are necessary toward the improvement of regional attenuation models.

oz ©LASI DEPREM HASARLARININ TAHMİNİ İÇİN STOKASTİK YÖNTEMLER Askan, Ayşegül Yüksek Lisans, İnşaat Mühendisliği Bölümü Tez Yürütücüsü: Prof. Dr. M. Semih Yücemen Temmuz 2002, 157 sayfa Deprem oluşumu ve yapısal davranıştaki belirsizlikler nedeniyle, deprem hasar tahminleri olasılıksal bir biçimde ele alınmalıdır. Bu çalışmada, Türkiye'deki az ve orta katlı betonarme binaların olası deprem hasarlarının tahmini için üç ayrı stokastik yöntem sunulmuştur. Bir hasar olasılık matrisi (HOM), belli bir takım kurallara uygun olarak tasarlanmış ve inşa edilmiş yapıların, değişik şiddetteki depremlere maruz kaldığında uğrayacağı hasarın olasılık dağılımını bir matris şeklinde gösterir. Bu çalışmada, ilk stokastik yaklaşım olarak, Türkiye'de son yıllarda meydana gelen depremlerde derlenen hasar verileri ile uzman görüşü birleştirilerek, her bir deprem bölgesi için `en iyi tahmin` hasar olasılık matrisleri geliştirilmiştir. İkinci yaklaşım, deprem yükü ile sismik dayanım büyüklüklerini rassal değişkenler olarak ele alan, güvenirlik kuramına dayalı bir modeldir. Bu modelde,olası deprem hasan, maksimum yer ivmesine veya deprem şiddetine bağlı olarak, hasar oranları dağılımı ile ifade edilmiştir. Üçüncü yaklaşım olarak, yakın zamanda meydana gelmiş depremlerden elde edilen hasar verileri üzerinde diskriminant analizi uygulanmış ve yöntem içinde yapılan sınıflandırmaya bağlı olarak, ilgili depremlerin şiddetlerine karşılık gelen hasar durumu olasılıkları hesaplanmıştır. Elde edilen hasar olasılık dağılımları, değiştirilmiş Mercalli şiddet ölçüsüne bağlı olarak ifade edilmiş ve üç yöntemle bulunan sonuçlar karşılaştırılmıştır. Anahtar Kelimeler: deprem hasar tahmini, hasar olasılık matrisi, kırılganlık eğrileri, güvenirlik kuramı, sismik dayanım indisi, diskriminant analizi, Düzce depremi. vı ABSTRACT STOCHASTIC METHODS FOR THE ESTIMATION OF POTENTIAL SEISMIC DAMAGE Askan, Ayşegül M.S., Department of Civil Engineering Supervisor: Prof. Dr. M. Semih Yücemen July 2002, 157 pages Due to uncertainties involved in both occurrences of earthquakes and structural responses, earthquake damage prediction has to be treated in a probabilistic manner. In this study, three stochastic methods, for the prediction of potential seismic damage to low and mid-rise reinforced concrete buildings in Turkey, are presented. A damage probability matrix (DPM) expresses what will happen to buildings, designed according to some particular set of requirements, during earthquakes of various intensities. In this study, as the first approach, `best estimate` damage probability matrices for each seismic zone are developed by combining expert opinion and the damage statistics compiled from the recent earthquakes occurred in Turkey. Second approach involves a reliability-based model, which treats the earthquake force and seismic resistance as random variables. This mmodel expresses potential seismic damage in the form of a damage rate distribution, which is a function of modified Mercalli intensity or peak ground acceleration. As the third methodology, discriminant analysis technique is utilized to carry out a statistical analysis on the damage data compiled during recent earthquakes that occurred in Turkey. Based on the classification procedure involved in this technique, the damage state probabilities corresponding to modified Mercalli intensity levels of the relevant earthquakes, are obtained. The stochastic damage profile obtained according to these three methods is expressed in terms of modified Mercalli intensity scale and the results are compared with each other. Keywords: earthquake damage estimation, damage probability matrix, fragility curves, seismic resistance index, reliability theory, discriminant analysis, Düzce earthquake. IV 157