1,721,026 research outputs found
Liquefaction-induced damage assessment in Golbasi city after the 6th February 2023 Türkiye earthquakes
No full textOn February 6th, 2023, at 4:17 a.m. local time, a devastating earthquake struck the territories of southeastern Türkiye and northwestern Syria. The moment magnitude recorded for the first strong quake was 7.7. Subsequently, numerous quakes of moment magnitude greater than 3 were recorded in the already affected areas. A further strong quake of magnitude 7.6 at 13:24 local time resulted in further extensive damage in the eleven provinces of Türkiye already hit. This paper focuses on the assessment of the earthquake-induced damage to the built environment observed in Gölbaşı city, located in the Adıyaman province of Türkiye close to the Gölbaşı Lake. The damage data have been collected through an in-situ reconnaissance performed by the Turkish author 10 days after the main seismic events. Analysis of the strong ground motions recorded in Gölbaşı city has been cross-checked with data on geological and subsoil conditions, also integrated with data reported in other studies, and the observed damage mechanisms. The features of the detected damage highlighted the presence of both inertia-induced effects, due mainly to the building vulnerability, and typical damage patterns related to the earthquake-induced liquefaction of the foundation soils, such as punching failure and consolidation settlements. This preliminary assessment shows the significance of this case for the advancement of the knowledge on earthquake-induced liquefaction and traces the route for deeper future studies
The Effect of the Significant Duration on the Site Response Analysis of Liquefiable Soils
No full textSite effects observed in Antakya after the Mw 7.7 Pazarcik and Mw 7.6 Elbistan Earthquakes on the 6th February 2023 (Türkiye)
No full textOn February 6, 2023 Eastern Türkiye was shaken by two consecutive catastrophic earthquakes of moment magnitudes 7.7. and 7.6, induced by a left-lateral strike-slip fault in Eastern Anatolian Fault Zone. The first earthquake with a moment magnitude 7.6 was felt at 4:17 local time in the morning, while, approximately nine hours later, the second earthquake with a moment magnitude 7.7 increased the massive damage that occurred in eleven provinces of Türkiye including Hatay, Kahramanmaraş, Adıyaman, Malatya, Osmaniye, Gaziantep, Kilis, Şanlıurfa, Diyarbakır, Adana and Elazığ. In this paper, a specific focus is devoted to show the site effects observed in Antakya after the strong shakings as revealed by an extensive analysis of the collected ground motion records and geological and geotechnical data. It is shown that basin effects are associated with a higher level of damage compared to areas with the same level of ground shaking but without detrimental conditions of the local soils. The lessons learned from this seismic event highlight the key role played by the seismic response analysis and related tools of microzonation studies for the mitigation of the seismic risk
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A comparison of equivalent linear and effective stress based nonlinear ground response analysis methods considering an alluvial soil profile in Izmir
No full textSahaya özel zemin davranış analizleri, TBDY-2018'e göre ZF yerel zemin sınıfına giren zeminlerin yüzeyindeki tepki spektrumunu elde etmek için yapılmaktadır. Bu çalışma kapsamında, İzmir ili, Bayraklı ilçesi Manavkuyu Mahallesine ait bir sondaj lokasyonunda eşdeğer doğrusal ve efektif gerilme tabanlı doğrusal olmayan zemin tepkisi analizleri yapılmıştır. Bu analizler hem DD-1 hem de DD-2 deprem seviyeleri için ayrı ayrı yapılmıştır. Pik yer ivmesinin etkisi de değerlendirilerek kayma birim deformasyonları ve yüzey tepki spektrumları baz alınarak doğrusal ve doğrusal olmayan analizlerden elde edilen sonuçlar karşılaştırmalı olarak yorumlanmıştır.Site-specific soil response analyses are performed to determine surface response spectra of soils that are classified as "ZF", according to TBDY-2018, Turkish Building Earthquake Code. Within the scope of this study, equivalent linear and effective stress-based non-linear ground response analyses were carried out considering a soil investigation performed at Manavkuyu District, Bayraklı, İzmir. The analyses were individually performed both for DD-1 and DD-2 earthquake levels. Taking the effect of peak ground acceleration into consideration, results obtained by linear and nonlinear analyses were comparatively interpreted considering shear strains and surface response spectra
Türkiye Mw 7.7 Pazarcık and Mw 7.6 Elbistan earthquakes of February 6th, 2023: Contribution of valley effects on damage pattern
No full textOn February 6th, 2023, southeastern Türkiye was shaken by two catastrophic earthquakes, close to northwestern Syrian border. The first earthquake (Pazarcık) occurred 45 km west of Gaziantep at 1:17:32 (UTC), with a shallow strike-slip faulting at a depth of approximately 8.6 km and a moment magnitude (MW) of around 7.7. The second event (Elbistan) took place 9 h later, 66 km north-east of Kahramanmaraş city center, also with shallow strike-slip faulting at a depth approximately 7 km and an MW of around 7.6. Turkish authorities reported a death toll of over 59,000 in Türkiye and about 8500 in Syria. The destructive effect of the earthquake resulted from widespread strong ground shaking, a rupture length exceeding 300 km, causing collapse of a large number of buildings. The catastrophic destruction of the built environment was accompanied by a range of other earthquake-related effects, including fault ruptures, landslides, and soil liquefaction. The aim of the study is to analyze the distribution of ground motion and their relationships with the observed damages for the two events. Spectral accelerations of key importance were assessed across a large area in the southeastern part of Türkiye. Notably, these accelerations were generally much higher than existing design spectra. A significant correlation between the observed concentration of damage and the significant amplification of motion induced by local soil conditions (such as soft soils and valley effects). The distinct tectonic structure of the region could be the main reason for the high amplification in the valleys (associated with basin effects), even at large distances from the epicenter, especially in correspondence with the bidimensional graben-type geological structures. The investigation delved into the analysis of four specific regions in detail: Antakya and Hassa (both in the Hatay province), Kahramanmaraş and Göksun. Notably, the observable valley effects were found to play a significant role and could account for the significant damage observed in these regions
Fiber ile donatılandırılmış kireç stabilize kilin donma çözünme etkisi öncesi ve sonrası mekanik özellikleri
No full textLime is known to be a hydraulic binder, particularly used in stabilization of soils of relatively high plasticity. On the other hand, fiber materials of high aspect ratio is used for reinforcement of soils, which help to constitute a structure counteracting the tensile stresses occuring in stabilized medium. In this study, the effect of inclusion of different types of fiber materials on clay/lime stabilized clay is investigated within an experimental framework. Lime stabilized clay samples reinforced using basalt or polypropylene fibers were subjected to standard Proctor, freeze-thaw, unconfined compressive strength and ultrasonic pulse velocity tests in order to determine their compaction and mechanical properties. A similar program excluding ultrasonic wave velocity tests were carried out on fiber reinforced specimens free of lime. Furthermore, selected specimens were subjected to Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) analyses to determine the microstructural aspects of stabilized medium. As expected, strength of clay/lime stabilized clay was improved by inclusion of both types of fibers. Although strengths of lime stabilized soils reinforced with polypropyene fiber was greater than those reinforced with basalt fiber in general, greatest strength was observed in 90-day cured basalt fiber reinforced specimen of fiber length, fiber content and lime content of 19 mm, 0.75% and 9%, respectively. Freeze-thaw effect was observed from the results of either strength or ultrasonic pulse velocity tests, these values are decreased due to freeze-thaw action. Losses in mass of specimens were determined along with measurements of ultrasonic pulse velocity and unconfined compressive strength by evaluation of the interrelationships among these parameters. Lastly, attempts using several numerical methods were made to model the strength of stabilized soils.Kireç hidrolik bir bağlayıcı olup, özellikle plastisitesi yüksek zeminlerin stabilizasyonunda kullanılmaktadır. Öte yandan boy/çap oranları yüksek olan fiber, zeminlerin donatılandırılmasında kullanılmakta, bu malzemenin kullanımı, ortamdaki çekme gerilmelerini karşılayan bir yapı oluşumuna yardım etmektedir. Bu çalışmada, değişik tipte fiber malzemelerin kireç ile stabilize edilen veya edilmeyen kil zeminin mekanik özelliklerine etkisi deneysel bir çerçevede incelenmiştir. Çalışmada bazalt ve polipropilen fiber ile stabilize edilen kil örneklerin bir standart Proktor, donma-çözünme, serbest basınç deneyleri ve ultrasonik dalga hızı deneylerine tabi tutularak sıkışma ve mekanik özellikleri belirlenmiştir. Bir kısım örnek fiber/kireç kombinasyonu ile stabilize edilerek benzer deneyler de bu örneklerin üzerinde de yapılmıştır. Bununla birlikte, seçilen örnekler üzerinde Taramalı Elektron Mikroskopisi (SEM) ve Enerji Dağılımlı Spektroskopi (EDS) görüntülemesi kullanılarak stabilize ortamın mikroyapısal özellikleri incelenmiştir. Beklendiği üzere, kireç içeren ve içermeyen örneklerin mekanik özellikleri hem bazalt hem de polipropilen fiberin kullanım ile gelişim göstermiştir. Genellikle polipropilen fiber ile güçlendirilen kireç stabilize kil örneklerin dayanımı, bazalt fiber ile stabilize edilen benzer örneklerin dayanımından fazla olsa da 90 günlük küre tabi tutulan örneklerden ağırlıkça % 0.75 oranında 19 mm uzunluğunda bazalt fiber içeren %9 kireç içeriğine sahip örnek en büyük dayanımı vermiştir. Donma-çözünme etkisi gerek dayanım deneylerinin sonuçlarından gerekse tahribatsız bir deney olan ultrasonik hız deneyi ölçümlerinden gözlenmiştir, dayanımlar ve ultra ses hızları düşmektedir. Örneklerin donma çözünme etkisinden sonra kütle kayıpları da kaydedilmiş, kütle kaybı ultrasonik ses hızı ve serbest basınç dayanımı arasındaki ilişkiler de ortaya konulmuştur. Son olarak değişik sayısal yöntemler ile stabilize zeminlerin dayanımı modellenmeye çalışmıştır
A study of seismic microzonation in the provincial center of Aydın (Turkey)
No full textBu çalışmada, Aydın ili Efeler İlçesi'nin dinamik zemin özelliklerinin incelenmesinden elde edilen veriler kullanılarak, sismik mikrobölgeleme çalışması yapılması amaçlanmıştır. Bu kapsamda, inceleme alanında yakın zamanda yapılan 144 sığ ve 4 derin sondajdan elde edilen geoteknik veriler derlenmiştir. Analizlerde kullanılmak üzere, NEHRP ve TBDY-2018'e göre zemin sınıflarını, zemin profilinin üst 30 m.'de ortalama kayma dalgası hızını(Vs30), spektral ivmeleri, spektral büyütmeleri içeren veri tabanı oluşturulmuştur. Bölgedeki deprem kaynakları belirlenerek, probabilistik sismik tehlike analizi yapılmıştır. Geoteknik zemin profillerinin ölçeklendirilmiş sismik tabankaya hareketlerine tepkisi, bir boyutlu eşdeğer lineer zemin tepki analizi yaklaşımı kullanılarak değerlendirilmiştir. Analizlerden elde edilen tahmini zemin tepki spektrumu değerleri, Türkiye Deprem Yönetmeliğindeki (2018) kriterlere göre hesaplanmıştır. Zemin büyütmesi, yüzey spektral ivmesi ve yer sarsıntı tehlikesinin inceleme alanındaki değişimi haritalanmıştır. Analiz sonuçları kullanılarak, inceleme sahasının Coğrafik Bilgi Sistemi tabanlı sismik mikrobölgeleme haritası oluşturulmuştur. NEHRP zemin sınıflandırmasına göre, inceleme alanının sadece C ve D sınıfı zeminlerden oluştuğu belirlenmiştir. Analizler, Aydın ili eski yerleşim yerleri zeminlerinin, daha sağlam olduğunu göstermiştir. İnceleme bölgesinde kuzeyden güneye doğru indikçe, zeminin mühendislik özelliklerinin zayıfladığı gözlenmiştir. Zemin profilinin baskın olarak, siltli kum, ve düşük plastisiteli siltler, az da olsa iyi derecelenmiş kum ve çakıldan oluştuğu gözlenmiştir. Bu tür zeminlerin sıvılaşmaya yatkın olması, kentin güneyinde yer altı su seviyesinin yer yer yüksek olması, inşaat alanlarında parsel bazlı özel incelemelerin gerekliliğini ortaya çıkarmıştır. Sonuç olarak, Efeler ilçesinde zemin mukavemeti iyileştirme çalışmalarının ve yapı tasarımlarının birlikte değerlendirilmesinin olası bir deprem tehlikesine hazırlık açısından vazgeçilmez bir önlem olacağı sonucuna varılmıştır.In this study, it was aimed to perform seismic microzonation study for the Efeler District of Aydın province based on the data obtained from the analysis of dynamic soil properties of the investigation field. In this scope, geotechnical data obtained from 144 shallow and 4 deep borings performed recently in the investigation area were compiled. A database containing soil classes in accordance with NEHRP and TBDY-2018 classification systems and average shear wave velocity in upper 30 m (Vs,30) and spectral accelerations and spectral amplification was formed in order to use in the analysis. A probabilistic seismic hazard analysis was carried out by compiling the seismic resources in the region. The response of geotechnical soil profiles to scaled seismic base rock motions was evaluated by using a one-dimensional equivalent linear ground response analysis approach. Estimated soil response spectra obtained from these analyses were calculated according to the criteria in the latest Turkish Building Earthquake Code (2018). The variations in both soil amplification, surface spectral accelerations and ground shake hazard were mapped. A geographic information system-based seismic microzonation map of the investigation field was built up by using the results of the analysis. It was determined that the investigation field composed of only C and D soil classes according to NEHRP soil classification system. The analyses showed that soils of better engineering properties underlay ancient settlements of Aydın city. Advancing from north to south in the investigation area, it was observed that the engineering properties of the soils became worse. A very low percentage of encountered soils were well-graded sand and gravel, the soil profile was predominantly composed of silty sand and silts of low plasticity. Based on the fact that the structure of such soils is prone to liquefaction and the groundwater level in the southern part of the city is high from place to place, it was revealed that it is necessary to make site-specific investigations in field application. Results of analyses show that in Efeler district, evaluation of the soil improvement methods and structural designs as a whole would be an indispensable measure in terms of preparedness to a possible earthquake hazard
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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