Yazar "Demirci, Alper" seçeneğine göre listele

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    Age, composition and paleoenvironmental significance of a Late Pleistocene eolianite from the western Black Sea coast of Turkey
    (Pergamon-Elsevier Science Ltd, 2013) Erginal, Ahmet Evren; Kiyak, Nafiye Gunec; Ekinci, Yunus Levent; Demirci, Alper; Ertek, Ahmet; Canel, Timur
    On the basis of field observations, thin section interpretations, microanalytical data, electrical resistivity survey and luminescence dating, the age, composition and internal structure of coastal eolianite on the west Black Sea coast at Sile, Istanbul, was studied for a combined interpretation of dune rock development and facies characteristics. Results demonstrate that the eolianite is made up of south-dipping, large-scale dune stratification, consisting mainly of quartz sand and, in particular, abundant ooids, as well as the binding cement which is composed of calcite and aragonite. Based on Electrical Resistivity Tomography (ERT) images, the eolianite has a thickness of between 3.5 m and 8 m and overlies a buried rugged topography that has developed on the Pliocene unit. This suggests the predominance of northerly winds that account for the landward removal of dune sands by offshore wind drift prior to carbonate cementation. Optically Stimulated Luminescence (OSL) dating estimations revealed that the initial deposition of the laminated eolianite layers on the underlying older unit took place at 138.57 +/- 13.65 ka, matching the Karangatian highstand or Marine Isotope Stage (MIS) 5e. (C) 2012 Elsevier Ltd and INQUA. All rights reserved.
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    An active extensional deformation example: 19 May 2011 Simav earthquake (Mw=5.8), Western Anatolia, Turkey
    (Oxford Univ Press, 2015) Demirci, Alper; Ozden, Suha; Bekler, Tolga; Kalafat, Dogan; Pinar, Ali
    The Simav Earthquake that occurred on 19 May 2011 in western Turkey was investigated on the basis of seismological data and geological observations. Approximately WNW-ESE trending surface ruptures were observed on the Simav Fault. The focal mechanism parameters of the earthquake (Mw = 5.8) and its aftershocks (Mw > 3.5) were estimated using time-domain moment tensor inversion. A total of 2245 events were located with Geiger's conventional absolute location method then relocated using the double difference (DD) algorithm. The calculated locations at a depths between 2 and 16 km were found to be consistent with Coulomb stress variation in the area. Average variance reduction (VR) of the solutions was calculated as similar to 70%. The focal parameters of strike dip and slip of the main shock, occurring at a depth of 11 km dipping towards the NNE, were estimated at 277, 62 and -92, respectively. The most striking indication of the study is that the area is dominated by normal faults with mainly WNW-ESE trends. It is also concluded that earthquakes in the region are caused by an active and regional NNE-SSW (N 12 degrees E) trending (sigma(3) axis) extension regime. The mean stress ratio is 0.80, indicating a triaxial stress state. This extension is probably associated with a slab-pull force and /or roll-back due to the complex subduction process of the African Plate beneath Anatolian block along both the Hellenic and Cyprus arcs in the eastern Mediterranean region.
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    Analysis of local site conditions through geophysical parameters at a city under earthquake threat: Canakkale, NW Turkey
    (Elsevier Science Bv, 2019) Bekler, Tolga; Demirci, Alper; Ekinci, Yunus Levent; Buyuksarac, Aydin
    Canakkale is the second province, after Istanbul, that has territories in both Asia and Europe. The city, also known as Dardanelles, is located on the Gallipoli peninsula in the northwest of Turkey, and the Biga peninsula which is an extension of Anatolia at the west. The region is tectonically quite active and it has high earthquake generation potential. The city has experienced a significant earthquake (Mw = 6.8) once again that occurred on May 24, 2014. In addition to these challenges, remarkable part of the city's territory and also potential new settlement areas are located on thick alluvium. Thus, mentioned-above disadvantages clearly increase the importance of this study, which focuses on determining the areas having different earthquake hazard potentials with regard to local site conditions by performing seismic risk assessments, as well as providing a basis for the preparation of settlement suitability maps on different scales that will lead knowledge for zoning plans. To that end, an integrated geophysical and geotechnical study was performed in a detailed manner. Multi-channel analysis of surface waves (MASW) and microtremor (MT) measurements were carried out at properly distributed 110 stations representing the whole survey area. The geotechnical study, planned to contribute geophysical interpretation, involved the drilling of 110 boreholes that are close to geophysical measurement stations. In addition to examining Vs30 variations based on the MASW, the ground dominant vibration period maps were also produced through MT time series analysis. In particular, the mean Vs velocity (Vs30) up to the first 30 m and the ground oscillation period change based on spectral amplitude ratios (HVSR) yielded substantial information that helped generate the seismic microzonation maps and also make the ground classification. These outputs contributed to exhibit the risk zones in the coastal city that has a dense and narrow settlement plan. (C) 2019 Elsevier B.V. All rights reserved.
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    Azimuthal Path Variations of Regional Body Wave Attenuation via Coda-Source Normalized Method: An Example from Eastern Marmara (NW Turkey)
    (Taylor & Francis Ltd, 2023) Demirci, Alper; Bekler, Tolga
    This study examines the body wave attenuation characteristics for the eastern section of the Marmara Region (NW Turkey). Qp and Qs values were obtained using the vertical and two horizontal components of the three-component broad-band data, respectively that recorded in a circular areal extent with 120 km radius centred at the ARMT station on the Armutlu Peninsula. The database was prepared according to back-azimuthal distributions, and data-packs representing 36 different back-azimuthal slices were subjected to the Extended-Coda-Normalization-Method to examine the azimuthal path-dependence of the attenuation characteristics of direct body waves in the region. While the region corresponding to the basins in the Marmara Sea with relatively low seismicity is represented by high Q values, low Q values were observed in areas with intense faulting and seismicity in the NE of the study area. Additionally, direction-independent attenuation functions for the region were calculated as Qp = 18 +/- 1f(0.92 +/- 0.2) and Qs = 38 +/- 1f(0.87 +/- 0.01) for P and S phases, respectively.
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    Büyük Menderes Grabeninde Cisim Dalgalarının Frekans Bağımlı Soğrulma Karakterinin Belirlenmesi
    (2019) Demirci, Alper; Bekler, Tolga
    Bu çalışmada, Büyük Menderes grabeninin kuzey sınırı boyunca gelişen fay toplulukları ve bunların Ege Denizi’ne doğru uzantılarıboyunca oluşmuş 66 deprem verisi kullanılarak bölgeye ait soğrulma karakteristikleri ortaya konmaktadır. Çalışmada, P ve Sdalgalarının soğrulma fonksiyonları, koda normalizasyon tekniği ile hesaplanmıştır. Çalışma kapsamında elde edilen sonuçlar,bölgede veya yakın civarında gelecekte olması muhtemel büyük depremlerin daha doğru bir şekilde modellenebilmesi ve sismik riskçalışmalarının da daha güvenilir sonuçlar elde edilmesi için gerekli olan temel parametrelerden biri olan sönüm ilişkilerini ortayakoymaktadır. Buna göre, S ve P sismik fazları için sırasıyla, Qs=79.2±14.6f 0.9±0.07 ve Qp=32.9±13.7f1.05±0.16 fonksiyonları eldeedilmiştir. Ayrıca 1 Hz’ den büyük frekanslarda QS/QP oranı ortalama ~1.75 olarak hesaplanmıştır. Elde edilen sonuçlara göre düşükQp ve Qs değerleri ve bunların oranları (QS/QP) saçılma etkisinin fazlalığını işaret etmekte ve bunun da çalışma alanındaki özellikleüst kabuktaki yoğun yanal heterojenitenin bir sonucu olduğu şeklinde yorumlanabilmektedir.
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    Çanakkale şehir merkezi sismik mikrobölgelendirmesi
    (Çanakkale Onsekiz Mart Üniversitesi, 2007) Demirci, Alper; Kaya, Mehmet Ali
    Bu sismik mikrobölgeleme çalışmasında, 46 istasyondaki elektrik özdirenç ve 44 istasyondaki mikrotremor ölçümleri ile yüzey jeolojisinin elektriksel ve dinamik özellikleri belirlenmiştir. Her bir özdirenç istasyonu bir boyutlu ters çözüm tekniğiyle değerlendirilmiş ve sonrasında farklı derinlikler için yer elektrik kesitleri oluşturulmuştur. Doğru akım özdirenç yöntemi sonucunda, çalışma alanının batı kesimlerinde Sarıçay havzası ile Çanakkale boğazı arasında kalan kısımda yüksek özdirençli birimlere rastlanmıştır. Bölgenin doğusuna gidildikçe azalan özdirenç değerleri havza içinde alüvonal tabakaları işaret etmektedir. Diğer yandan, mikrotremör ölçümlerine uygulanan bazı veri işlem aşamaları sonrasında her istasyon için hakim titreşim periyotları ve zemin büyütme değerleri hesaplanmış ve dağılım haritası oluşturulmuştur. Mikrotremor çalışmaları sonucunda çalışma alanının hakim titreşim periyodunun 0.15-1 sn. aralığında değiştiği özellikle Sarıçay havzasının merkezinde ve güney kısımlarında alüvyonu temsil eden 0.5-1 sn.'lik değerler aldığı görülmektedir. Bununla yanında, çalışma alanın yüksek topoğrafyalı ve nispeten yaşlı birimleri barından kuzey kesimlerinde, sıkı ve sağlam birimleri temsil eden küçük periyot değerleri gözlenmektedir. Bölgede açılmış bazı sondaj kuyularında gözlenen ve S dalgası hız bilgisi ile hakim titreşim periyotlarının birlikte kullanılması temeline dayanan Kanai formülü ile hesaplanan alüvyon kalınlıkları arasındaki uyumu vurgulamak amacıyla karşılaştırmalar yapılmıştır. Çalışmanın sonucunda alternatif yerleşim alanlarının araştırılması veya olumsuz zemin koşullarına karşı birtakım zemin iyileştirme tekniklerinin uygulandıktan sonra yapılaşmaya gidilmesi önerilmektedir. Anahtar Kelimeler: Hakim titreşim periyodu, Mikrotremor, Özdirenç, Ters çözüm, Zemin büyütmesi
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    Canakkale Settlement Risk Reduction Studies and Evaluation of Disaster Awareness
    (Afet ve Acil Durum Yonetimi Baskanligi (AFAD), 2022) Bekler, Tolga; Cifci, Sait; Bekler, Feyza Nur; Demirci, Alper
    Taking precautions against disasters and implementing tasks is possible with a good planning. In cases where there is no planning, there is the risk of being damaged by disasters. Losses due to disasters in Turkey are quite high. For this reason, one of the necessary elements to reduce losses and take precautions to take measures is to raise awareness of the public. Although earthquake comes to mind first when the concept of disaster is mentioned, it is seen in different types of disasters in our country. The most common natural disasters in Canakkale are earthquakes, floods, lightning strikes, landslides and forest fires. In this study, it is aimed to define the natural disasters that occurred in Canakkale and its vicinity and to minimize the loss of life and property in these natural disasters with risk reduction studies with respect the surveys. To achieve this aim, disaster awareness level was evaluated by statistical surveys of the disaster management system in Canakkale based on basic definitions and concepts related to disaster management and risk reduction. © 2022 Turk Deprem Arastirma Dergisi. All rights reserved.
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    Çanakkale, Afet farkındalığı, Risk Azaltma
    (2022) Bekler, Tolga; Çifçi, Sait; Bekler, Feyza Nur; Demirci, Alper
    Afetlere karşı önlemlerin alınması ve görevlerin uygulanması iyi bir planlama ile mümkün olmaktadır. Planlamaya sahip olunmayan durumlarda, afetlerden zarar görebilme riski ortaya çıkmaktadır. Türkiye’de afetler nedeniyle verilen kayıplar oldukça fazladır. Bu nedenle önlemlerin alınması yönünde ilk olarak kayıpları azaltmak ve önlem almak için gerekli unsurlardan biri de halkın bilinçlendirilmesidir. Afet kavramı denilince akla ilk olarak deprem gelse de ülkemizde farklı türlerde afetler de görülmektedir. Çanakkale’de en çok gerçekleşen doğa kaynaklı afet türleri; deprem, sel, yıldırım düşmesi, heyelan ve orman yangınlarıdır. Bu çalışmada Çanakkale ve çevresinde gerçekleşen doğa kaynaklı afetler tanımlanmış bu afetlerdeki kayıpların risk azaltma çalışmalarıyla en az seviyede gerçekleşmesine yönelik birey temelli yansımalar ve tepkiler, anket çalışması ile araştırılmıştır. Bu amaca ulaşmak için afet yönetimi ve risk azaltma ile ilgili temel tanım ve kavramlar bazında Çanakkale’de afet yönetim sistemi saha anket çalışmaları ile afet bilinç seviyesi değerlendirilmiştir.
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    Characterization of a Landslide using Seismic Refraction, Electrical Resistivity and Hydrometer Methods, Adatepe - Canakkale, NW Turkey
    (Environmental Engineering Geophysical Soc, 2011) Bekler, Tolga; Ekinci, Yunus Levent; Demirci, Alper; Erginal, Ahmet Evren; Ertekin, Can
    Seismic refraction and electrical resistivity surveys were carried out to characterize a landslide that occurred near the Canakkale-Lapseki-Bursa highway, in northwest Turkey. Hydrometer analyses were also performed to highlight the composition of the slip surface material. The combined interpretation of the methods yielded the mass of the landslide body and the possible subsurface nature of a basal slip plane. Sediment-size fraction maps show that the slip surface material contained an excessive amount of clay. The clay-rich slipping layer was observed to a maximum depth of 4-5 in marked by a low (2-4 ohm-m) resistivity zone, contrasting with the underlying sand-rich beds with relatively higher resistivities (>6 ohm-m). A velocity variation ranging between similar to 1,250-1,500 m/s also characterized this water-saturated slipping zone. Results indicated a buried failure surface under the studied shallow slide mass, which appeared to be a prolongation of the long upward-concave slip surface of the old landslide area to the east. Thus, future reactivations can be expected along basal slip surfaces of both recent and old landslide areas, which may pose a risk for the road structure and vehicular traffic along the active Canakkale-Lapseki-Bursa highway.
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    Coğrafik Konuma Özel Tasarım Spektrumlarının Betonarme Yapı Performansına Etkisi
    (2020) Karaşin, İbrahim Baran; Işık, Zeynep Ercan; Demirci, Alper; Aydın, M. Cihan
    Bir bölgenin depremselliği, yerel zemin koşulları ve yapısal özellikler yapıların deprem etkisi altındakidavranışlarını ve risklerini belirlemede kullanılan önemli parametrelerdir. Yapılar ile ilgili analizlerde o bölgenindepremselliği, spektrum eğrileri ile ifade edilebilmektedir. 2019 yılında yürürlüğe giren Türkiye Bina DepremYönetmeliği ile noktaya özel spektrum eğrileri kullanılmaya başlanmıştır. Bu çalışma kapsamında Türkiye’dekiyedi farklı coğrafik bölgeden birer il seçilerek coğrafik konumun hem deprem parametrelerine hem de yapıperformans hesaplamalarını hangi düzeyde etkilediği ortaya konmaya çalışılmıştır. Ankara, Antalya, Diyarbakır,Erzurum İstanbul, İzmir ve Samsun illeri için 50 yılda aşılma olasılığı %10 (tekrarlanma periyodu 475 yıl) olanve Türkiye Bina Deprem Yönetmeliği’nde DD-2 olarak belirtilen yer hareket düzeyi ile yerel zemin sınıfı ZEolarak dikkate alınmıştır. Her il için kısa periyot harita spektral ivme katsayısı, en büyük yer ivmesi, en büyük yerhızı, yerel zemin etki katsayıları, tasarım spektral ivme katsayıları ile yatay ve düşey elastik spektrum eğrisi içinhesaplamalar yapılmıştır. Çalışma ile farklı geometrik konumlarda bulunan fakat aynı zemin özellikleri ve yerhareketi olmasına rağmen deprem parametrelerinin değişimi incelenmiştir. Coğrafik konumun yapı performanshesaplamalarına etkisi ortaya koymak adına tüm illerde aynı yapısal özelliklere sahip yedi katlı betonarme bir yapıseçilmiştir. Seçilen örnek betonarme yapı için her il için analizler gerçekleştirilmiştir. Yapı analizinde zeminözelliklerinin dikkate alındığı statik adaptif itme analiz kullanılmıştır. Elde edilen tüm sonuç değerlerikarşılaştırılmıştır. Coğrafik konum değişikliği hem deprem parametrelerini hem de yapısal analiz sonuçlarıdoğrudan etkilemektedir. Çalışma, Türkiye Bina Deprem Yönetmeliğinin sahaya özel deprem parametrelerinin birkazanım olduğu sonucunu ortaya çıkarmıştır. Herhangi bir noktada yerel zemin koşulları ve yapısal özellikler aynıolsa bile bölgenin depremsellik öğelerinin dikkate alınması gerekmektedir.
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    Delineation of the seawater-freshwater interface from the coastal alluvium of Kaleköy-Gökçeada, NW Turkey
    (2008) Ekinci, Yunus Levent; Demirci, Alper; Ertekin, Can
    In this study, combined geophysical methods were performed to determine layered seawater-freshwater interface which is under natural conditions through a semipervious layer in a coastal alluvium of Gökçeada-Turkey. The surveyed area named Kaleköy is located in the northeastern part of Gökçeada. Electrical resistivity tomography technique with using dipole-dipole electrode configuration was performed over two profiles. The interpretation of the two-dimensional inversion of the acquired resistivity data delineated the seawater-freshwater interface successfully. Additionally to the resistivity data, two-dimensional seismic refraction tomography survey was also conducted to characterize the alluvium properties in terms of saturation conditions. It was determined that the soil is characterized with unconsolidated sediments. This study yielded useful information about the geometry of seawater body under the freshwater. The interface was determined at the depth of 7-8 in approximately and presents an undulated surface. Moreover, it was observed that seawater intruded far distant than the length of the survey area (>150 m). © 2008 Asian Network for Scientific Information.
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    Depositional Characteristics of Carbonate-Cemented Fossil Eolian Sand Dunes: Bozcaada Island, Turkey
    (Coastal Education & Research Foundation, 2013) Erginal, Ahmet Evren; Ekinci, Yunus Levent; Demirci, Alper; Avcioglu, Mustafa; Ozturk, Muhammed Zeynel; Turkes, Murat; Yigitbas, Erdinc
    Erginal, A.E.; Ekinci, Y.L.; Demirci, A.; Avcioglu, M.; Ozturk, M.Z.; Turkes M., and Yigitbas, E., 2013. Depositional characteristics of carbonate-cemented fossil eolian sand dunes: Bozcaada Island, Turkey. Journal of Coastal Research, 29(1), 78-85. Coconut Creek (Florida), ISSN 0749-0208. Coastal eolianite on the south coast of Bozcaada Island, Turkey, was investigated by field observations, petrographic and climatological examinations, and electrical resistivity tomography data. The 4- to 7-m-thick eolianite, including rhizolith morphotypes characterized by root tubules and bifurcated root casts, demonstrates dune-sand accumulation during the Upper Pleistocene. Our results showed that paleowind drift and recent windblown sand drift on the island are similar. The dune sands exhibit various cement types formed of calcite and aragonite, such as micrite encrustations, meniscus and gravitational cements, and in particular, void fills. Dune-sand accumulation took place on the truncated surface of Miocene deposits. Geophysical data showed the existence of large weathered cavities within the eolianite and a high-angle normal fault, which displaces the eolianite, together with the underlying Miocene unit.
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    Eolianite and coquinite as evidence of MIS 6 and 5, NW Black Sea coast, Turkey
    (Elsevier Sci Ltd, 2017) Erginal, Ahmet Evren; Kiyak, Nafiye Gunec; Selim, Hamit Haluk; Bozcu, Mustafa; Ozturk, Muhammed Zeynel; Ekinci, Yunus Levent; Demirci, Alper
    This paper discusses the implications of a lowstand carbonate eolianite and overlying transgressive sequence of coquinite at Sile on the Turkish Black Sea coast based on composition, depositional characteristics and optical age estimations. The cross-bedded eolianite is a mixed ooid quartz grainstone in composition, yielding a depositional age matching MIS 6. It formed at the backshore of the paleobeach with the supply of sediment the from the beach face and offering insights into the drift of mixed shallow marine carbonates and siliciclastics together with radial ooids by onshore winds from a subaerially exposed high- to low-energy ooid shoals and oolitic sand complexes which developed parallel to the shoreline on the shallow shelf margin. During this lowstand, a low-relief dune retaining a record of opposing paleowind directions than that of prevalent northeasterly winds of today appears to have been lithified to form dune rock (aeolinite) under drier conditions compared to the present. Coinciding with MIS 5e, shallow marine coquina beds resting unconformably on the eolianite indicate the occurrence of the Mediterranean transgression during the last interglacial, as confirmed by benthic foraminifera within the high-salinity tolerant coquina shells. (C) 2017 Elsevier B.V. All rights reserved.
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    First note on Holocene coquinite on Thrace (Black Sea) coast of Turkey
    (Elsevier Science Bv, 2012) Erginal, Ahmet Evren; Ekinci, Yunus Levent; Demirci, Alper; Elmas, Elmas Kirci; Kaya, Hakan
    In this paper, preliminary results concerning the nature, subsurface structure and age of carbonate-cemented coquinite extending along a 1.5-km long and 40-m wide loose coquina beach on the Thracian (west Black Sea) coast of Turkey are presented. An Electrical Resistivity Tomography (ERT) survey showed that the coquinite has a maximum thickness of about 2 m and comprises seaward dipping buried 20 m-wide slabs under beach materials at the backshore. Cemented by low-magnesian calcite, the coquinite contains various bivalvia, benthic foraminifera, calcareous nannofossils or coccoliths and quartz sands. Diagenesis of the coquinite occurred as the result of sequential cementation, starting with the precipitation of micritic envelops typical of a marine phreatic zone. This early stage was followed by pore-lining cements and bladed rims composed of equal-sized subhedral and anhedral crystals of calcite, suggesting evidence of meteoric phreatic and meteoric vadose environments, respectively. Calibrated values from radiocarbon dating of four bulk samples of bivalvia revealed that the coquinite shells were deposited between 3730 and 2850 years BP. During that period the sea-level was similar to the present at an early stage then dropped to 2 m due to Phanagorian regression (between 3200 and 2200 BP), which is evidenced by consecutive cementation patterns of distinctive origin. (C) 2012 Elsevier B.V. All rights reserved.
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    First record of beachrock on Black Sea coast of Turkey: Implications for Late Holocene sea-level fluctuations
    (Elsevier, 2013) Erginal, Ahmet Evren; Ekinci, Yunus Levent; Demirci, Alper; Bozcu, Mustafa; Ozturk, Muhammed Zeynel; Avcioglu, Mustafa; Oztura, Erdal
    We present new data on the diagenetic characteristics, subsurface nature and radiocarbon ages of beachrock from the Thracian Black Sea coast of Turkey, indicative of sea-level changes and climatic conditions favoring lithification of beach sands between 5.4 ka and 3.5 ka cal BP. Micrite coatings and succeeding meniscus cements typify diagenetic history and suggest a two-stage cementation over this timeframe. The early cements are typical of upper intertidal zone when the sea-level was likely similar to that of today. The ensuing intergranular bridges refer to an approximate 2 m decline in sea-level, favoring downward percolation of meteoric waters related to subaerial exposure, marked by a reduction in Mg concentration and dissolution pits on early cement coatings. Formation of beachrock during this bimillennial period could be associated with relatively drier conditions promoting the precipitation of connective cements. (C) 2013 Elsevier B.V. All rights reserved.
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    Frequency-dependent body-Q and coda-Q in Karliova Triple Junction and its vicinity, eastern Turkey
    (Tubitak Scientific & Technological Research Council Turkey, 2019) Demirci, Alper
    A dataset obtained from six broadband stations of 111 small- to moderate-sized local events that occurred between 2010 and 2018 was analyzed to reveal the frequency-dependent seismic body (body-Q) and coda (coda-Q) wave attenuation characteristics of three tectonic branches of the Karliova Triple Junction: the Varto Fault Zone (VFZ), North Anatolian Fault Zone (NAFZ), and East Anatolian Fault Zone. The magnitude range was between 2.8 and 6.1 with shallow (<10 km) focal depths. The maximum station-event distance was selected as not to exceed 120 km. Frequency-dependent Qc functions were determined using the single back-scattering model with four lapse time lengths (20, 30, 40, 50 s) while the extended coda normalization method was performed to estimate the body wave attenuation functions for seven central frequencies varying from 1.5 Hz to 18 Hz. The minimum and maximum Qp values were 7 at 1.5 Hz for the VFZ and 739 at 18 Hz for the NAFZ, respectively. Qs values were observed between a minimum of 26 for VFZ and maximum of 1259 for NAFZ. Additionally, coda-Q results show a strong lapse time dependency between Q(0) and n; exhibiting a decrease in n by an increase in Q(0), with an ascending lapse time. Comparing the three subregions of the Karliova Triple Junction, VFZ appears to have a significantly higher attenuation for all Q types and Qs/Qp ratios while the NAFZ has relatively low attenuation.
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    Frequency-dependent body-Q and coda-Q in Karlıova Triple Junction and its vicinity, eastern Turkey
    (2019) Demirci, Alper
    A dataset obtained from six broadband stations of 111 small- to moderate-sized local events that occurred between 2010and 2018 was analyzed to reveal the frequency-dependent seismic body (body-Q) and coda (coda-Q) wave attenuation characteristicsof three tectonic branches of the Karlıova Triple Junction: the Varto Fault Zone (VFZ), North Anatolian Fault Zone (NAFZ), and EastAnatolian Fault Zone. The magnitude range was between 2.8 and 6.1 with shallow (<10 km) focal depths. The maximum station-eventdistance was selected as not to exceed 120 km. Frequency-dependent Qc functions were determined using the single back-scatteringmodel with four lapse time lengths (20, 30, 40, 50 s) while the extended coda normalization method was performed to estimate the bodywave attenuation functions for seven central frequencies varying from 1.5 Hz to 18 Hz. The minimum and maximum Qp values were7 at 1.5 Hz for the VFZ and 739 at 18 Hz for the NAFZ, respectively. Qs values were observed between a minimum of 26 for VFZ andmaximum of 1259 for NAFZ. Additionally, coda-Q results show a strong lapse time dependency between Q0 and n; exhibiting a decreasein n by an increase in Q0, with an ascending lapse time. Comparing the three subregions of the Karlıova Triple Junction, VFZ appears tohave a significantly higher attenuation for all Q types and Qs/Qp ratios while the NAFZ has relatively low attenuation.
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    GEOPHYSICAL IMAGING SURVEY IN THE SOUTH NECROPOLIS AT THE ANCIENT CITY OF PARION (KEMER - BIGA), NORTHWESTERN ANATOLIA, TURKEY: PRELIMINARY RESULTS
    (Univ Agean, Dept Mediterranean Stud, 2012) Ekinci, Yunus Levent; Kaya, Mehmet Ali; Basaran, Cevat; Kasapoglu, Hasan; Demirci, Alper; Durgut, Cemal
    Parion is one of the most important settlements located in the ancient Troas region, in which the city of Troy was the center. Many remarkable and precious archaeological remains have been unearthed so far which point out the city's importance during the Hellenistic and Roman Age. In this study, a first attempt to obtain high resolution images of the subsurface of Parion to guide the archaeological trenches was made by an initial geophysical survey applying Electrical Resistivity Tomography (ERT) technique. The apparent resistivity data, collected using pole-dipole electrode configuration along 11 transects, were inverted by two- and three-dimensional smoothness-constrained least squares algorithms. Relatively compatible results were obtained from two inversion processes. Parallel transects showed the resistivity distribution in three-dimensional images and thus both the horizontal and vertical extents of the anomalous zones were displayed. Additionally, some high anomaly zones located at the end of the first six transects were backed up by archaeological trenches. Thus, taking into account these findings, the other resistivity anomalies located at the different parts of the surveyed area are thought to be the most promising locations for archaeological excavations.
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    Geophysical imaging survey in the South Necropolis at the ancient city of Parion (Kemer - Biga), Northwestern Anatolia, Turkey: Preliminary results
    (Henan University, 2012) Ekinci, Yunus Levent; Kaya, Mehmet Ali; Başaran, Cevat; Kasapo?lu, Hasan; Demirci, Alper; Durgut, Cemal
    Parion is one of the most important settlements located in the ancient Troas region, in which the city of Troy was the center. Many remarkable and precious archaeological remains have been unearthed so far which point out the city's importance during the Hellenistic and Roman Age. In this study, a first attempt to obtain high resolution images of the subsurface of Parion to guide the archaeological trenches was made by an initial geophysical survey applying Electrical Resistivity Tomography (ERT) technique. The apparent resistivity data, collected using pole-dipole electrode configuration along 11 transects, were inverted by two- and three-dimensional smoothness-constrained least squares algorithms. Relatively compatible results were obtained from two inversion processes. Parallel transects showed the resistivity distribution in three-dimensional images and thus both the horizontal and vertical extents of the anomalous zones were displayed. Additionally, some high anomaly zones located at the end of the first six transects were backed up by archaeological trenches. Thus, taking into account these findings, the other resistivity anomalies located at the different parts of the surveyed area are thought to be the most promising locations for archaeological excavations. Copyright © 2012 MAA.
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    Geophysical investigations at Agadere Cemetery, Gallipoli Peninsular, NW Turkey
    (Taylor & Francis Ltd, 2014) Buyuksarac, Aydin; Yalciner, Cahit Caglar; Ekinci, Yunus Levent; Demirci, Alper; Yucel, Mehmet Ali
    Historical cemeteries are challenging targets for geophysical prospection but some non-destructive imaging techniques may be successful for mapping buried cemeteries if applied appropriately. Ground-Penetrating-Radar (GPR) has generally been considered to be the only geophysical method for determining cemeteries; however, Electrical-Resistivity-Tomography (ERT) and Magnetic-Imaging (MI), may determine geophysical traces of such cemeteries. Thus, as a first attempt at applying geophysical methods in the cemetery area of the Gallipoli Peninsula, these techniques were used to explore the buried graves at Agadere Cemetery. In this study, measured apparent resistivity data were processed using a two-dimensional (2D) tomographic inversion scheme. Resultant resistivity depth slices and volumetric resistivity images clearly showed the anomaly zone, which may be attributed to anthropogenic burials. Additionally, three-dimensional (3D) visualization of GPR results indicated some anomalies, much like the resistivity anomalies in terms of location. MI data were processed using linear transformations and an analytic signal image map presented anomaly zones located in some parts of the area, which are in agreement with those obtained by ERT and GPR surveys. Results derived from data processing techniques showed that these methods are suitable for bordering the locations of other buried historical graves in areas that have the same geological environment in the Peninsula.