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Öğe 2007 ve 2018 Deprem Yönetmelikleri Kullanılarak Farklı Zeminlere Göre ve Farklı Kentler İçin Elde Edilen Tasarım İvmelerinin Karşılaştırılması, Kapadokya Örneği(2021) Karaca, Hakan2019 itibarı ile yürürlüğe girmiş olan Türkiye Bina Deprem Yönetmeliği (TBDY-2018) ile zemin parametrelerinde çok önemli yenilikler getirilmiş ve zemin-yapı etkileşiminin daha gerçeğe yakın modellenebilmesini mümkün hale gelmiştir. Zeminin özellikle büyütme ve küçültme etkisinin yeni şartnamede yer alması, yönetmeliğin bilimsel verilere daha uygun hale gelmesini sağlamıştır. Bu kapsamda, TBDY-2018’den resmi olarak yürürlüğe girmeden önce yürürlükte olan Deprem Bölgelerinde Yapılacak Binalar Hakkında Yönetmelik (DBYBHY-2007) kapsamında yapıların tasarımında kullanılan tasarım ivmeleri ile yeni deprem şartnamesine göre uygulanacak tasarım ivmelerini karşılaştırılması yapılmış ve Kapadokya bölgesi illerinin il merkezlerinde zemin koşullarına bağlı olarak tasarım ivmelerinin ne kadar artıp azaldığını belirlenmiştir. Çalışmanın sonunda, herhangi bir salınım periyodu için, 2018 deprem yönetmeliğine göre tasarlanacak yapıların tasarımında kullanılacak tasarım ivmelerinin 2007 yönetmeliğine göre nasıl değiştiği ile ilgili bir örüntüye rastlanmamıştır. Sadece salınım periyotları büyüdükçe, yeni deprem şartnamesine göre kullanılacak olan tasarım ivmelerinin, eski yönetmelik değerlerine oranının azaldığı görülmüştür. Böylelikle, salınım periyotları daha yüksek olan yapıların tasarımında kullanılacak tasarım ivmelerinin eski yönetmelik değerlerine oranı, düşük salınım periyotlara sahip yapıların tasarım ivmeleri oranlarına göre daha düşük olacaktır.Öğe 2023 Maraş depremleri ve Niğde’deki yer hareketliliği(2024) Karaca, Hakan6 Şubat 2023 tarihinde gerçekleşen Pazarcık (Mw=7.7) ve Elbistan depremleri (Mw=7.6) başta Malatya’dan Hatay’a kadar Doğu Anadolu Fay Hattı ve yakın çevresini etkilemiştir. Etkilenen illerden bir tanesi de Niğde’dir. Can kaybının yaşanmadığı ve deprem nedeniyle yıkılan bina olmayan il merkezinde, birçok yapı hasar görmüş ve ekonomik kayıplar meydana gelmiştir. Niğde il merkezinin (34.70E,37.90N) Pazarcık depreminin merkez üssüne (37.04E,37.29N) uzaklığı 217.3 km ve Elbistan depreminin merkez üssüne (37.24E,38.09N) uzaklığı ise 223.2 km olmakla birlikte depremler çok şiddetli hissedilmiştir. Bu çalışmada bu iki depremin yer hareketliliği açısından Niğde ilindeki etkisi incelenmiş, Niğde il merkezinde bulunan ivmeölçer tarafından kaydedilen kayıtlar çözümlenmiş ve tasarım ivmeleri ile ölçülen ivme değerleri karşılaştırılmıştır.Öğe A new approach in understanding the influence of irregular framing over the lateral drift in reinforced concrete structures(Gazi Univ, Fac Engineering Architecture, 2023) Karaca, Hakan; Aydin, Ersin; Severcan, Metin HakanThe approximate prediction of lateral performance of buildings without any analytical study requires quite a lot of knowledge and experience in the field for an engineer and an architect as well. An algorithm is required to enhance the mentioned predictions that mostly rely on the knowledge and experience. In this context, in order to quantify the degree of irregularity in framing of the structure in plan column density maps are developed, and thanking to the developed quantification method, the derivation of the relationship between the degree of irregularity and the maximum global roof drift of the structure is aimed. Knowing that the degree of irregularity has a negative impact on the lateral performance, in order to derive the relationship between the two, a regular structure is designed and 16 irregular models based on the regular model are developed. Linear response spectrum analysis and non-linear pushover analysis are conducted to obtain the global drifts and based shears. For linear analysis, the fundamental periods of vibration, mass participation ratio and eccentricity are monitored, while in non-linear analysis the global drifts are monitored. Shortly, the quantification of the irregularity in plan, is a novel approach which a potential to strengthen the hands of the designers, engineers and architects, also could be treated an evaluation tool as an improved global drift and lateral performance prediction method.Öğe A New Method for the Evaluation of Interevent Time Distribution of Earthquakes, Case of Turkey(Afet ve Acil Durum Yonetimi Baskanligi (AFAD), 2021) Karaca, HakanSeveral distribution models are used in order to model the distribution of the inter-event times of earthquakes. The performances of these models are mostly tested through goodness-of-fit tests but not through putting the models into application. Moreover, there is not a definitive conclusion about which model can be the best fitting one. Within this context, the objective of study is to test a number of distribution models in simulating the distribution of Turkish earthquakes in temporal domain. The earthquake time series are subjected to analysis for its IET distribution and future earthquakes are simulated by using Monte-Carlo techniques. The variation of number of earthquakes per unit time and the standard deviations are monitored for each IET model. Finally, log-normal distribution is identified as the most successful distribution model in modelling and simulating the earthquake time series. © 2022 Turk Deprem Arastirma Dergisi. All rights reserved.Öğe A Quantitative Study on the Earthquake Forecast Verification for the Northwestern Turkey(2020) Karaca, HakanSeismic events have a pattern of recurrence in magnitude, time and space. Considerable effort is being spent to identifyseismic patterns and successfully predict future earthquakes by using the recognized patterns. As a result of these intensiveefforts, a variety of methods has been proposed. As the knowledge and experience in the field accumulated in parallel to thevariety of the methods proposed, it was deemed necessary to test the performance of some of the highlighted methods,especially considering the wide reception of methods utilizing SSS, PI and RI. The performance of these methods inforecasting the earthquakes has been selected for investigation.The investigated area is the region bounded by 270-320E in longitudes and 39.80-420N in latitudes, well known for the NorthAnatolian Fault. The period of coverage has been selected such as to maximize the length with the minimum magnitude ofcompleteness. As a result of such optimization, the period from 1973 to 2019 has been selected with minimum magnitude ofcompleteness being determined as 3.8. In order to measure the relative performance of the methods, ROC analysis has beenutilized. The method based on SSS has been adapted to the related ROC procedures, while the results of PI and RI methodsare already suitable for the evaluation by ROC procedures.After the analysis was completed, according to the ROC procedures, none of the methods were singled out in forecastperformance. However, when the ratio of hits versus total alarms and the area covered by the alarms, PI method outperformstwo other methods by its efficiency.Öğe An Investigation into the Earthquake Migration Patterns in Marmara Region, Turkey(Maik Nauka/Interperiodica/Springer, 2021) Karaca, HakanThe seismic migration patterns can be associated with the existing geophysical setting, the tectonic movements and the geographical distribution of seismicity. The right identification of these patterns would lead to the better hazard analysis, forecasts and precise predictions. So, in an attempt to develop a method for the identification of seismic migration pattern, the Marmara Region of Turkey is selected for investigation. Actually, seismicity in the considered region is a consequence of the movement of the neighboring plates along the system of faults that makes up Northern Anatolian Fault (NAF). Accordingly, it was decided to investigate whether the earthquakes have an identifiable migration pattern in the direction of movement. As a single assumption, the migration pattern, if it exists, is assumed to follow Markovian behavior. At the end of the study, the results shed a light not only on the pattern of seismicity but also on the geophysical processes causing earthquakes.Öğe Application of Markovian models for non-ergodic and non-stationary earthquake times series for the identification of seismic patterns and future projections(Seismological Soc China & Inst Geophysics, China Earthquake Admin, 2020) Karaca, HakanThe current earthquake forecast algorithms are not free of shortcomings due to inherent limitations. Especially, the requirement of stationarity in the evaluation of earthquake time series as a prerequisite, significantly limits the use of forecast algorithms to areas where stationary data is not available. Another shortcoming of forecast algorithms is the ergodicity assumption, which states that certain characteristics of seismicity are spatially invariant. In this study, a new earthquake forecast approach is introduced for the locations where stationary data are not available. For this purpose, the spatial activity rate density for each spatial unit is evaluated as a parameter of a Markov chain. The temporal pattern is identified by setting the states at certain spatial activity rate densities. By using the transition patterns between the states, 1- and 5-year forecasts were computed. The method is suggested as an alternative and complementary to the existing methods by proposing a solution to the issues of ergodicity and stationarity assumptions at the same time.Öğe Generation of synthetic catalog by using Markov chain Monte Carlo simulation and inverse Poisson distribution(Springer, 2021) Karaca, HakanA synthetic seismic catalog assists not only in reducing the uncertainties in computations of seismic hazard, but also in simulating the future seismic events, which, if modeled accordingly, provides a forecast model. The seismicity forecast provides additional time-dependent information that may complement the seismic hazard. Within this context, in an attempt to generate a synthetic catalog and simulate future seismicity at the same time, Markov chain Monte Carlo (MCMC) simulation techniques are employed. The temporal distribution of earthquakes is modeled through hidden Markov model (HMM) and periods with different inter-event time distributions are determined, which are then assigned with different states. Along with the global magnitude and spatial distribution, the inter-event time distribution for each state is used to simulate future events with magnitude, occurrence location, and time assigned accordingly. In the end, a synthetic catalog is generated which indeed is a detailed forecast as well.Öğe Hazard functions and conditional probability of earthquake occurrences in major fault zones in Turkey(Islamic Azad Univ, Mashhad Branch, 2023) Karaca, HakanAmong several distribution characteristics, temporal distribution characteristics of earthquakes provide the most crucial information on the temporal patterns of past seismicity. Identification of such patterns is required for seismic hazard, forecast studies and also simulation of future seismicity. The confusion of how to model the past temporal patterns does limit further development:. Though the Poisson model is routinely used in hazard modelling, its validity is often questioned. Furthermore, the question as to which model best represent past temporal patterns of earthquake occurrence is not answered yet. Within this context, in this study, to investigate the interevent time (IET) distribution, two seismically active regions in Turkey are selected where the seismic activity never diminishes and the hazard remains high. These regions, namely the western end of the North Anatolian Fault Zone and East Anatolian Fault Zone are known to produce moderate or large magnitude earthquakes. Four distributions, namely, exponential, gamma, Weibull and lognormal models are tested for how well they fit the earthquake records of the two faults, and importantly, the hazard functions that is instantaneous rate of occurrence of events, and conditional probabilities are also developed for performance evaluation. In the end, it is observed that, each model has flaws in identification of temporal pattern of earthquake occurrences and forecasting earthquakes.Öğe Seismicity Simulation and a Forecast Model Based on Monte Carlo Simulation Techniques and Performance of Distribution Models(World Scientific Publ Co Pte Ltd, 2021) Karaca, HakanIn seismic hazard studies, simulation techniques are exploited relatively less compared to other statistical methods. The main purposes of their use were merely scientific: either to reduce uncertainty in seismic hazard or to test the consistency of a forecast. Its limited exploitation in the field does not mean that the method could not be exploited further. Given sufficient data and with the right models, a full-scale simulation is possible, which in fact becomes a forecast with future timing, location and magnitude of future events are simulated. Within this context, the main purpose of this study is to layout a method to create a full scale simulation with all the parameters namely the time, location and magnitude of an earthquake is simulated. For that purpose, in addition to the main parameters defining past seismic patterns, namely the temporal, spatial, magnitude distributions, the combined spatio-magnitude distribution is also modeled. As another improvement compared to the current procedures, occurrence date is assigned to the simulated event according to the inter-event time distribution, which enhances the simulation procedure. The eventual temporal distribution and the associated earthquake rates are checked with the original earthquake rate for its consistency. In the end, a simulation procedure, which can also be used as a forecast model is developed to improve the existing procedures further.Öğe SELECTION OF THE MOST APPROPRIATE GROUND MOTION PREDICTION EQUATION FOR LOCAL SEISMIC HAZARD ANALYSIS(2020) Karaca, HakanTogether with the ever-increasing number of global and local Ground Motion Prediction Equations (GMPEs) and thecomplexity of the functional forms, incompatibility problems arise in the selection of the most appropriate GMPE for a specificlocation. Associated with the incompatibility issues, practitioners face a compromise over the precision of prediction becausethe functional form of the used GMPE that might be developed by considering influential parameters, which might not beavailable for the considered location. Hence, a modification is required to adjust the considered GMPE to local conditions byusing the local ground motion data. The sensitivity of the parameters of the selected GMPEs to the local seismic propagationpatterns can be determined only after the adjustment. Together with the attempts to solve the incompatibility and sensitivityproblem, the selection of the most appropriate GMPE becomes the selection of the most suitable functional form.The aim of this study is to select the most appropriate GMPE form for Eskişehir through the guidance of the above statements.A number of GMPEs are selected according to the criteria of wider utilization and recognition. All the candidate GMPEs weresubjected to adjustments, including some minor modifications and the calibration of the coefficients by using the indigenousdata. Then, a number of statistical and visual procedures were applied including the performance test of the adjusted GMPEswith the records of the two largest earthquakes that occurred in the region. The study highlights the influence of the localseismic behavior on the performance of various functional forms of the candidate GMPEs.Öğe The Influence of Soil Parameters of TEC-2019 over the Amount of Structural Material Used and Roof Drift of Structures, A Case Study(Gazi Univ, 2022) Karaca, HakanThe new Turkish Earthquake Code adopted in 2019, was developed to minimize the gap between the application and the current level of knowledge in the field and to respond to ever-growing need in the application of new design methods and design different type of structures. Especially, the problems experienced due to varying ground responses to the earthquakes is more realistically addressed with the introduction of the already applied approaches in different foreign earthquake codes. Within this context, in the study, the influence of the newly introduced ground types and related parameters over the design of new structures is investigated. For that purpose, sample structures are gathered, and these structures are adopted to each ground type by modification of its vertical structural members and the change in the dimensions of vertical members, amount of reinforcement and the roof drifts of the modified structures are monitored. Consequently, the overall influence of the new ground parameters over the structural design is investigated. As the main result of this study, the studied parameters are determined to be one of the influential factors in the design and have strong influence potential for the designers, investors and the authorities in the industry.Öğe YAPISAL TASARIM BAĞLAMINDA 2007 VE 2019 DEPREMYÖNETMELİKLERİNİN KARŞILAŞTIRILMASI, NİĞDE ÖRNEĞİ(2020) Karaca, Hakan; Oral, S. Merve; Erbil, Merve01.01.2019 tarihinde yürürlüğe giren Türkiye Bina Deprem Yönetmeliği (TBDY-2019) ile mevzuatımız halihazırda Dünyada kullanımda olan benzerleri ile daha uyumlu hale getirilmiş olup, yapıların deprem etkileri altındaki davranışlarını daha gerçekçi bir yaklaşımla modellemede akademik bilgi ile uygulama arasındaki farkı giderme amacıyla yenilikçi bir yaklaşımlahazırlanmıştır. Bu yeni yaklaşımların yapı tasarımına olan etkisini incelemek ve daha iyi anlaşılmasını sağlamak üzere, Niğde İl Merkezinde; TBDY-2019'a göre tasarlanan 5 adet binanın, 2007 tarihli Deprem Bölgelerinde Yapılacak Yapılar Hakkında Yönetmelik’e (TDY-2007) göre çözümlemeleri gerçekleştirilerek kullanılan malzeme miktarı ve performansları açısından değerlendirilmiştir. Ayrıca, mimarileri aynı kalmak üzere, TDY-2007'ye göre uyarlanan yapıların, kullanılan malzeme miktarlarının ve performanslarının değişimi izlenmiştir. Böylelikle, yönetmeliklerin yapı tasarımına olan etkisi, mimarisi aynı yapılarda kullanılan malzeme miktarlarının, malzeme verimliliğinin ve yapısal performanslarının karşılaştırılması ile irdelenmiş, maliyetlere de yansıması kaçınılmaz olan farklılıklar derlenmiştir. Çalışma sonunda, malzemenin verimli kullanımı açısından dayanım sınırlarına göre yapılan boyutlandırma sonrasında, yeni yönetmeliğe göre tasarlanacak bir yapı da daha fazla beton kullanılması gerekeceği, ancak donatı miktarın da genelde azalma eğilimi olduğu gözlemlenmiştir.Öğe YHTD’lerin Değerlendirilmesinde Yeni Bir Yöntem(2021) Karaca, HakanYer hareketi tahmin denklemlerinin sayılarının günden güne artması (YHTD), geliştirme aşamasında kullanılan verilerin artması ve buna paralel olarak denklemlerin daha karmaşık hale gelmesi, kullanıcılar açısından kolaylık değil daha çok külfet getirmiştir. Sismik tehlike analizi (STA) için hangi denklemin daha uygun olduğu ve daha kesin sonuçlar verebileceği konusu bir süredir kullanıcıları meşgul etmekte, denklem geliştiricileri ise denklemlerin geçerlilik koşulları konusunda zorlamaktadır. Denklemlerin uzaklık, deprem büyüklüğü ve diğer parametrelere bağlı değişken performansları ve özellikle belirsizlikleri, denklemlerin seçimi konusunda kullanıcıları mantık ağacı gibi yöntemleri geliştirmeye sevk etmiştir. Ancak bu yöntemle, belirli sayıda YHTD seçimi ile sadece tek YHTD seçilmesinin oluşturabileceği belirsizlik ve yanlış tercih olasılığı en aza indirilmeye çalışılmıştır. Ancak, şurası bir gerçek ki bu yönteminde yaklaşık yöntem olduğu ve en gerçekçi sonucu değil ancak en yakın sonucu verdiği bilinerek, yeni çözümler sunma amacı ile çalışmalar devam etmektedir. Bu çalışmada da, böyle bir bakış açısı ile tamamıyla yeni bir yöntem olan eşivme eğrileri ile uyumluluk yöntemi kullanarak, hâlihazırda geliştirilmiş denklemler değerlendirilmiştir. Ayrıca denklemlerin performansı diğer denklemlerle karşılaştırılarak yerel etkilere de vurgu yapılmıştır. Bu yöntemle, depremlerin yıkıcı etkilerinin daha yüksek olduğu alanlarda ki performansının önemi ön plana çıkartılarak yapılan değerlendirmenin, en doğru denklemin seçimi açısından önemi vurgulanmıştır.
