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Öğe 3D modelling and structural investigation of the central Volcanics in Slovakia using magnetic data(2013) Bektaş, Özcan; Büyüksaraç, Aydin; Rozimant, KamilThe Central volcanics, located in central part of Slovakia, is characterized by intense andesitic volcanic activity that resulted in the formation of stratavolcanoes and dome complexes of Middle and Late Miocene age. The basement area has been affected tectonically resulting in the formation of horst and graben structures. The Central Slovakian Volcanic Field (CSVF) exhibits a very complex magnetic anomaly. A 3-km upward continued magnetic map indicates a deep-seated source for this magmatism. The pseudogravity transformation of the upward continued anomaly has also been constructed. This anomaly was modelled by a 3D-method. The anomalous body lies between the depths of 4.4 to 8.5 km beneath the surface of the CSVF. Volcanic structures and some lineaments are presented on the maxima of the horizontal gradient of the pseudogravity anomaly map. They are well correlated with the structural map of CSVF.Öğe Archaeo-geophysical Investigations in Ahlat Seljuk Square Cemetery, Bitlis, Eastern Anatolia TURKIYE(2023) Büyüksaraç, Aydın; Kulaz, Mehmet; Bektaş, Özcan; Dumankaya, Oktay; Ekinci, Yunus Levent; Koşaroğlu, SinanGeophysical methods are frequently used in archaeological sites to obtain significant priori information. These methods assist archaeological excavation strategies by indicating the anomaly zones that may be associated with buried remains. Archaeo-geophysical methods are based on measuring the physical parameter contrast (e.g. magnetic susceptibility, dielectric constant, resistivity, density) between the buried archaeological remains and the covering environment. In this study, magnetic and ground penetrating radar methods were applied to contribute to excavation planning. The study area is a historical cemetery and has been used as an interment area for about 1000 years. Considering the information obtained from the previous excavations, the research depth was initially planned not to exceed 3 meters in general, but information up to 10 meters was obtained. We aimed at determining possible graves in the area outside the walls of Square Cemetery in Ahlat (Bitlis) district. After performing some data-processing steps to the raw data obtained, magnetic and ground penetrating radar anomaly maps were produced. Based on the distinguishable geophysical traces most promising locations were determined and suggested for archaeological excavations.Öğe Bedrock Investigation Based on Shear Wave Velocity (Vs) on the Sites of High-Rise Buildings(Springer Science and Business Media Deutschland GmbH, 2025) Büyüksaraç, Aydın; Ateş, Barış; Bektaş, Özcan; Pamuk, Eren; Işık, ErcanThe foundations of high-rise buildings are naturally designed with more importance than other structures. Therefore, it is necessary to know the soil conditions very well during design. High-level information production is needed, especially for designs to be made on unstable soils with high earthquake risk. In this study, which was carried out on a very weak soil, the first 30 m from the surface were used with the Multi-Channel Analysis of Surface Waves (MASW) method, while precise Vs values were obtained with the Refraction Microtremor (ReMi) method in the depth range of 30–100 m. The depth value of engineering bedrock (260 m), where Vs reached a velocity value of 760 m/s, was obtained with the Spatial Autocorrelation (SPAC) method. By combining these three data sets, Vs velocity change was modelled up to a depth of 550 m. The PS logging measurement was made in the 200 m deep well, which could be opened with difficulty, and compared with the 1-dimensional Vs velocity model, and the changes were plotted on the same graph to see their compatibility with each other. Additionally, the ground dominant vibration period was calculated using the single station microtremor method and was found as 1.4 s. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.Öğe CAESAREA GERMANICIA (?) ARKEOJEOFİZİK ARAŞTIRMALARI(Kahramanmaraş Sütçü İmam Üniversitesi, 2022) Dumankaya, Oktay; Bektaş, Özcan; Koşaroğlu, Sinan; Büyüksaraç, AydınKahramanmaraş merkez ilçelerinden biri olan Dulkadiroğlu ilçesinde ortaya çıkartılan kalıntıların Roma Dönemi’nde kurulan Caesarea Germanicia’ya ait olduğu düşünülmektedir. Bölgede, Kahramanmaraş Müzesi başkanlığında Doç. Dr. Oktay DUMANKAYA’nın bilimsel danışmanlığında gerçekleştirilen araştırma ve kazılar, arkeolojik kültür kalıntılarının yayılım alanının 150 hektardan fazla olduğunu ortaya koymuştur. Gerçekleştirilen araştırma ve kazılarda her ne kadar Roma Dönemi kültür kalıntılarının yoğunluğu dikkati çekse de Bizans, Selçuklu ve Osmanlı Dönemi seramik parçalarının tespit edilmiş olması, araştırma sahasında, yüzyıllarca süren kesintisiz bir yerleşimi işaret etmektedir. Yer Radarı (GPR) 6 profil boyunca gerçekleştirilmiştir. Elde edilen sonuçlar hem birbirleriyle hem de mevcut yüzey koşulları ile karşılaştırılmış ve GPR derinlik haritaları oluşturulmuştur. GPR derinlik kesitleri incelendiğinde 4 önemli yansımaya rastlanmıştır. Bu yansımaların 3 tanesi arkeolojik yapı kalıntılarına ait diğer 1 tanesi ise metal malzemeden (boru) kaynaklı olduğu yorumlanmıştır. GPR kesitlerinde belirlenen yansımaların, İS. 5-6. yüzyıla tarihlediğimiz Erken Bizans Dönemi Villa Rustica veya bir Roma Hamamı duvar kalıntılarına ve metal boruya ait olduğu görülmüştür. Yer radarı ölçümlerinde yapı duvarlarını paralel olarak kesen başka duvarların olduğu belirlenmiştir. Arkeolojik kazılar sonucunda söz konusu bu duvarların İS. 5-6. yüzyıla tarihlediğimiz Erken Bizans Dönemi yapısından farklı olarak çamur katkılı moloz taştan yapılmış olduğu anlaşılmıştır. Kazılarda tespit edilen ve 11-13 yüzyıla tarihlendirilen seramik parçalarından bu yapının Orta Bizans Dönemi’nde tekrar kullanılmış olduğunu işaret etmektedir.Öğe A Comparative Evaluation of Earthquake Code Change on Seismic Parameter and Structural Analysis; A case of Turkey(2022) Büyüksaraç, Aydın; Işık, Ercan; Bektaş, ÖzcanTurkey, which is one of the countries with high seismic risk, has made significant changes in both seismic risk maps and seismic design codes over time by adapting to these developments. Information about the important changes in the last two earthquake maps and provisions in Turkey was given and the effects of these changes on structural and seismic parameters were examined in this study. In order to make comparisons of seismic parameters, seven different settlements from seven different geographical regions in Turkey were taken into account which have the same seismic risk in the previous earthquake risk map. Seismic moments were also calculated separately for these locations to describe the intensity of future tectonic activity. With the current earthquake hazard map, geographical location-specific earthquake risk has been started to be used instead of regional risk. For the selected settlements with the same seismic risk in the previous map, the seismic risks were found high in some and low in some with the current hazard map. In addition, structural analyses were carried out for the sample reinforced-concrete building with the same structural characteristics in these seven different settlements in order to reveal the effect of the code and map change on the structural analysis. While the target displacements expected from the structures for the settlements with the same seismic risk take the same values, the target displacements are obtained differently for each, since the specific design spectrum is used for each location with the current map.Öğe Coulomb Stress Analysis in Nemrut Caldera (East Anatolia, Türkiye)(2024) Alkan, Hamdi; Bektaş, Özcan; Büyüksaraç, AydınIn volcanic areas, seismic events with low energy occur before seismic activity or due to the movement observed in the magma. These earthquakes, which are caused by the expansion-contraction movement that has been revealed in different studies and is mostly observed in the magma chamber, can be recorded with continuous observations. On the other hand, it is not easy to distinguish between tectonic and volcanic origins of earthquakes occurring in volcanic areas. In this study, Coulomb stress analysis was carried out using earthquakes in the Nemrut Stratovolcano, which is located in the eastern Türkiye and is at the westernmost end of a volcano arc, and it was concluded that the stress is related to the Nemrut Caldera, therefore the positive stress caused by the expansion of the magma chamber of the Nemrut Volcano creates tremors.Öğe Determination of historical graves by ground penetrating radar method: Sakarya Field Battle (August 23 – September 13, 1921, Turkey)(2022) Koşaroğlu, Sinan; Kamacı, Züheyr; Erdoğan, Selim; Bektaş, Özcan; Büyüksaraç, AydınThe Sakarya Field Battle was the last phase of the forward operation of the Greek Asia Minor Army, which started at the end of March 1921. Although there are contradictory numbers regarding the losses of the parties in the Sakarya Field Battle in the literature, it is generally accepted that the Turkish Army lost 5,713 martyrs. The Ground Penetrating Radar (GPR) method was applied to determine the accuracy of findings observed on the surface and to determine burial sites. Geophysical anomalies were detected in 2D profiles from the obtained results. It was determined that the Turkish side buried the martyrs in east-west direction, depending on their religious traditions. The detected anomalies were evaluated in two and three dimensions and the boundaries of the burial areas and the approximate depths of the burials were obtained. The results obtained from data processing techniques showed that the GPR method is suitable for determining the locations of historical graves on battlefields. The new martyrs found as a result of the studies are thought to be soldiers whose fate was unknown, recorded as ‘missing’ in the records.Öğe Development of magnetic flux leakage device as a non-destructive method for structural reinforcement detection(2022) Bektaş, Özcan; Kurban, Yunus Can; Özboylan, BuketNon-destructive measurement techniques are used to identify engineering construction components without causing any negative effects on their use as construction components in the future. Contrary to this, conventional techniques cause damage to the structure. The magnetic flux leakage (MFL) method is a non-destructive test technique commonly used to assess the physical status of construction materials. Within the framework of this study a magnetic flux leakage device was produced to detect the properties of reinforced concrete construction elements. The produced magnetic flux leakage device was used for measurements in 4 different test systems created in the laboratory environment and the results were interpreted. Thus, it was revealed that the detection of reinforcement in structures can be performed more rapidly and without damage with the MFL method.Öğe Doğu Anadolu bölgesinin Curie noktası derinliği ve jeotermal gradyanının jeofizik yöntemlerle araştırılması(Cumhuriyet Üniversitesi, 2006) Bektaş, Özcan; Büyüksaraç, AydınÖZET Yüksek Lisans Tezi DOĞU ANADOLU BÖLGESÎ'NİN CURIE NOKTASI DERİNLİĞİ VE JEOTERMAL GRADYANININ JEOFİZİK YÖNTEMLERLE ARAŞTIRILMASI Özcan BEKTAŞ Cumhuriyet Üniversitesi Fen Bilimleri Enstitüsü Jeofizik Mühendisliği Anabilim Dalı Danışman: Yrd. Doç. Dr. Aydın BÜYÜKSARAÇ Doğu Anadolu Bölgesi 2 km'lik yüksek bir platodan oluşmuş yüksek topoğrafyalı bir bölgedir. Havadan manyetik ve gravite verileri Maden Tetkik ve Arama Genel Müdürlüğü'nce (MTA) 1978 - 1989 yılları arasında yapılan çalışmalar çerçevesinde ölçülmüştür. Elde edilen veriler yeraltı yapılarının karmaşıklığını yansıtmaktadır. Çalışma alanına ait toplam alan rezidüel (artık) havadan manyetik anomali haritası, MTA tarafından ölçülmüş Türkiye'nin rejyonal (bölgesel) havadan manyetik anomali haritasından elde edilmiştir. Rezidüel (artık) havadan manyetik veriye alçak geçişli süzgeç uygulanmış ve süzgeçlenmiş bu verilerden Curic Noktası derinlikleri hesaplanmıştır. Manyetik anomalilerin üst ve orta derinlikleri, bütün alan için Güç Spektrumu yöntemiyle hesaplanmıştır. Daha sonra proje alanının tamamında Curie noktası derinlik haritası hazırlanmıştır. Doğu Anadolu bölgesindeki Curie noktası derinliği 12.9-28.3 km arasında değişmektedir. En sığ Curie noktası derinliği Doğu Anadolu Bölgesi'nin Kuzey ve Güney kısımlarında gözlenmektedir. Böyle değerlendirmeler kabuktaki sıcaklıkların göstericisi olabilir. Çünkü manyetik mineraller, kayaçlar içerisindeki hakim manyetik mineralleri doğal mıknatıslanmalarını Curie sıcaklığında kaybederler. Bu noktaya Curie Noktası Derinliği (CND) adı verilir. Manyetik verilerden elde edilen Curie Noktası Derinliğinin hesaplaması önemlidir. Doğu Anadolu gibi yoğun ve genç tektonik etkinliğin gözlendiği genç bölgelerdeki ısı akısı gözlemleri, yüksek sıcaklıkların genç volkanik birimlerle uyumlu olduğunu yansıtır. Ancak bu durum tektonik sentezlerde kabuksal ya da mantosal ısı akısının göstergesi değildir. Doğu Anadolu'da görülen geniş yayılımlı ısıl etkinlik, yüksek çözünürlüklü jeofizik yöntemlerle incelenmelidir. Anahtar Kelimeler: Havadan manyetik Anomaliler, Gravite verisi, Güç spektrumu, Curie noktası derinliği, Doğu Anadolu, Üst kabuk yapısıÖğe Geophysical variations during the total solar eclipse in 2006 in turkey(TUBITAK, 2011) Ateş, Abdullah; Büyüksaraç, Aydin; Bektaş, ÖzcanIt has been observed that some geophysical parameters could be changed during a solar eclipse. We have therefore measured gravity and magnetic fields during solar eclipses. We also measured the gravity field during the previous eclipse on the 11th of August, 1999. Gravity measurements on the 29th of March, 2006 are compared with previous gravity measurements at the same location during the eclipse on the 11th of August, 1999. Both showed the same behaviour during the eclipses. Gravity measurements showed fluctuations during both eclipses. A decrease in the intensity of the magnetic field was observed. Low-pass filtered magnetic data show peculiarity during the eclipse which can be correlated with the fluctuations in the gravity fields. Copyright ©TÜBİTAK.Öğe Havadan manyetik anomaliler kullanılarak Orta Anadolu volkanik karmaşığındaki volkanik bacaların oluşum mekanizmaları ve derinliklerinin hesaplanması(2006) Büyüksaraç, Aydın; Bektaş, Özcan; Arısoy, M. Özgü; Ateş, AbdullahOrta Anadolu Volkanik karmaşığı (OAVK) 13 milyon yıldır volkanik etkinliğin egemen olduğu bir bölgedir. Bu aktivite, OAVK'da yersel olarak bir karmaşık jeolojik yapının oluşmasına neden olmuştur. Bu durum bölgeye ait havadan manyetik anomali haritasındada gözlemlenebilmektedir. Daire şekilli anomaliler, volkanik kraterleri göstermektedir. Volkanik bacaların bazıları, önceki araştırıcılarca hazırlanan haritalarda gösterilmemiştir. Bir başka değerlendirme yöntemi Euler Dekonvolüsyon yöntemiylede çalışma alanındaki volkanik çıkışların taban derinliği bilgilerine ulaşılmıştır. Sonuçlar önceki çalışmalardan bilinen temel bilgilerle çoğunlukla uyum sağlamaktadırÖğe Importance of Bedrock Depth Knowledge in Basins: Çanakkale (Dardanalles) Case History(Springer Science and Business Media Deutschland GmbH, 2022) Büyüksaraç, Aydın; Karaca, Öznur; Eyisüren, Onur; Bektaş, Özcan; Işık, ErcanIt is not correct to produce the necessary information for structuring, especially in environments such as Çanakkale, which exhibit a basin structure, without determining the bedrock or the strict ground conditions in bedrock. This approach is the basis of earthquake resistant building design. In this study, which was carried out to determine the bedrock/seismic foundation depth for the central settlement of Çanakkale and to define the basin structure to a certain extent, microgravity measurements were taken on a large scale, and the study area was modelled in three dimensions based on the obtained gravity data. By taking long-term microtremor measurements, one-dimensional depth-shear wave (Vs) velocity models were obtained using the Rayleigh ellipticity method. A depth map of the engineering bedrock was created, in which the velocity Vs reached to 2500 m/s. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.Öğe Investigation of Site Characterization and Vulnerability in Antakya (Turkey) under Basin Effect(2023) Büyüksaraç, Aydın; Bektaş, Özcan; Işık, Ercan; Över, Semir; Kaçın, SelçukIt is very important and necessary to know the depth of the bedrock in determining the soil behavior. However, determining the depth of bedrock spatially is a very difficult and costly process. The depth of the bedrock can be obtained by using the dominant vibration frequency obtained by the microtremor data. The bedrock depth map was created with the correlation produced from the dominant vibration frequencies obtained from microtremor measurements made in Antakya (Turkey). In bedrock calculations at low frequencies, the value range shows scattering. In the vulnerability analysis for Antakya soils, a low level of vulnerability (Kg = 6) was obtained in the east and northeast of the area. It has been observed that the S-wave velocity (Vs) in this area is lower than 406 ms-1. In this case, this value has been accepted as the vulnerability threshold value in Antakya soils. Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) were obtained for each location by using earthquake ground motion levels with 2%, 10%, 50%, and 68% probability of exceedance in 50-year periods. The PGA values in the region range from 0.43 to 0.47 g for earthquakes with a return period of 475 years.Öğe Sakarya Meydan Muharebesi Savaş Alanındaki Erozyona Uğramış Siper Hatlarının Yer Radarı (GPR) Yöntemi ile Belirlenmesi(2021) Koşaroğlu, Sinan; Kamacı, Züheyr; Bektaş, ÖzcanSakarya Meydan Muharebesi, hem Türk Devletinin tarihi hem de Dünyanın enuzun süreli ve en büyük meydan savaşı olması yönünden oldukça önemtaşımaktadır. Bu savaşta Sakarya Nehri doğusunda 1921 yılında Türk Kuvvetleri ileYunan Kuvvetleri savaşmışlar ve her iki taraftan da çok fazla insan hayatınıkaybetmiştir. Doğa Koruma ve Milli Parklar Genel Müdürlüğü’nün 2015 yılındabaşlattığı kapsamlı çalışmalarla Şehit Defin Alanları ile Siper hatlarının konumlarıbelirlenmektedir. Dönemin şartları göz önüne alındığında ve Bölgesel Jeomorfolojikyapıya uygun olarak siper hatları oluşturulmuştur. Bu hatlar imkansızlıklar vezaman kısalığından dolayı bir çok bölgede 1-1.30 metre derinliğinde hazırlanmışboy çukuru olabilecek alanlardır. Bu çalışmada savaş esnasında kullanılan ancaksavaştan sonra sedimantasyon etkisi ile kaybolmaya yüz tutmuş siper hatlarının yerradarı (GPR) yöntemi ile belirlenmesi amaçlanmıştır. Yüksek frekanslı ve GenişBand (80-950 MHz) GPR yöntemi ile uydu görüntülerinde takip edilebilen ancakyüzeyde izi kaybolmuş siper hattı boyunca 2 ve 3 boyutlu ölçümler alınarak siperhatlarının devamlılığı ve sedimantasyon sınırları başarılı bir şekilde tespitedilmiştirÖğe Statistical and seismotectonic analyses of the Marmara region under existing stress regime in the west of the NAFZ(Springer Science and Business Media Deutschland GmbH, 2025) Alkan, Hamdi; Öztürk, Serkan; Bektaş, Özcan; Büyüksaraç, AydınThe Marmara Region is an active tectonic region in northwestern Türkiye, which comprises some important strike-slip active fault mechanisms and important tectonic units, located near the western part of the North Anatolian Fault Zone. In the historical and instrumental period, the Marmara Region experienced large/devastating earthquakes. Considering this continuous activity, in this study, we investigate the tectonic structure and performed future seismic hazard estimation of the region based on some seismotectonic parameters. For this evaluation, we plot the Coulomb stress change maps of 1912 Mürefte-Şarköy, 1953 Yenice-Gönen and 1999 İzmit mainshocks with the earthquakes (MW ≥ 4.5) that occurred in the study region after 2003. For the estimation of b-value, occurrence probabilities and return periods of earthquakes, we used a homogenous local seismicity catalogue consisting of 119.029 events for the period between 1912 and 2023. In the findings of this study, the lower b-values and increasing Coulomb stress changes which are trigger stress failure compatible are observed in the west and northwest of the Marmara Sea. In contrast, the higher/moderate b-values and decreasing Coulomb stress values are observed in the east and southeast of the Marmara Sea. The results of probability assessments show that an earthquake with Mw = 6.5 may occur with a probability of 98% in the west of the Marmara Sea after 2025. As a remarkable fact, a comprehensive assessment of these types of variables will supply important findings for earthquake hazard and potential in the study region. © The Author(s) under exclusive licence to Institute of Geophysics, Polish Academy of Sciences 2024.Öğe THE CAESAREA GERMANICIA (?) OF ARCHEOGEOPHYSICAL INVESTIGATIONS(2022) Dumankaya, Oktay; Bektaş, Özcan; Koşaroğlu, Sinan; Büyüksaraç, AydınThe remains unearthed in the Dulkadiroğlu district, one of the central districts of Kahramanmaraş, are thought to belong to Caesarea Germanicia, which was founded in the Roman Period. Research and excavations carried out by the Kahramanmaraş Museum and us in the region have revealed that the spread of archaeological cultural remains is more than 150 hectares. Although the concentration of Roman Period cultural remains in the research and excavations was remarkable, the discovery of Byzantine, Seljuk, and Ottoman Period ceramic pieces indicates an uninterrupted settlement in the research area for centuries. However, as can be seen in the images, the dense residential texture in the region is one of the biggest obstacles to archaeological research and excavations. Because, in order to carry out archaeological excavations of the identified structures, expropriations are required. However, the expropriation period covers an average of 2-4 years, which makes it difficult to conduct scientific research. Archeogeophysical methods provide information about the location, depth, and dimensions of the archaeological remains by applying them from the surface, without causing any damage to the archaeological remains sought. In this context, Ground Penetrating Radar (GPR) measurements were carried out to determine the quality of the mosaic-based structure on 445 layout, which were previously unearthed through illegal excavations in 2019, and the parcels on which it extends. GPR was carried out along 6 profiles. The obtained results were compared both with each other and with the existing surface conditions, and GPR depth maps were created. When the GPR depth sections were examined, 4 important reflections were found. It has been interpreted that 3 of these reflections belong to the archaeological building remains and 1 of them originates from a metal material (pipe). It was determined that the depth of the archaeological remains identified in the GPR sections started at a depth of approximately 20 cm. As a result of the excavation, it was seen that the reflections determined in the GPR sections belonged to the wall remains and metal pipe. As a result of archaeological excavations, it was determined that the GPR reflections belong to the remains of the walls of the Villa Rustica of the Early Byzantine Period or a Roman bath, as well as a metal pipe. In the measurements of the ground radar, it was determined that other walls cut the building walls in parallel. As a result of archaeological excavations, it was understood that these walls were made of rubble stone with mud additives. It was discovered during archaeological excavations and was discovered in the 11th-13th centuries AD. One of the ceramic fragments indicates that this structure was used again in the Middle Byzantine Period.
