Plio-quaternary evolution of the Kucuk Menderes Graben southwestern Anatolia, Turkey

The Kucuk Menderes Graben (KMG) is part of the horst-graben system of southwestern Anatolia (Turkey), bounded by the Bozdag horst in the north and the Aydin horst in the south. The Plio-Quatemary evolution of the KMG has been evaluated using the nature of the Miocene-Quaternary fill sediments and palaeostress analysis of slip data measured in different parts of the graben

Coğrafi bilgi sistemleri ve uzaktan algılama kullanılarak veri kaynaklı heyelan afeti tayini

The purpose of this thesis is to generate and evaluate a concise system of data driven landslide hazard assessment procedure. The Asarsuyu catchment area and Bolu Mountain highway pass are selected for this purpose In this study, three data domains, which are remote sensing products, geological maps and topographical maps are used. The landslides of four different historical periods are interpreted using aerial photographs. Land cover is extracted from satellite images. Thirteen sets of parameter maps are produced from geological and topographical maps and from remote sensing products. In order to store the information of these parameter maps in a concise thematic database a 25x25 meter grid is overlaid to the area. Two different sets of points are defined. First one representing the properties of slided masses and the other set representing the conditions contributing to the sliding phenomena. The information falling on these points are stored in five separate thematic landslide attribute databases, as two main databases are Seed Cells and Slided Mass Databases, with accessory three other as, Polystats, Fuzzystats and photo-characteristics databases. Following the creation of the databases, theinformation stored are evaluated and preliminary landslide generating decision rules are extracted. In conjunction with these preliminary results a hazard assessment procedure, starting from the least detailed and simple ranging up to most complex statistical analyses are initiated. Finally a relative accuracy assessment procedure is carried out using the hazard maps produced. It is found that the most accurate, reliable and realistic results concerning the landslide hazard assessment of Asarsuyu catchment are obtained through logistic regression analyses. The results of landslide hazard assessment of Asarsuyu catchment shows that: the northern slopes of the Asarsuyu catchment is classified as very low hazard due to the presence of low population, undisturbed dense forest land cover, being very distant to E-5 highway and to the major active fault and the favorable lithological conditions. The southeastern slopes especially the Bolu Mountain Highway pass are definitely on very high hazard class due to the removal of lateral supports by E-5 highway cut slopes, close location to active faults, high disturbance of the land cover, high traffic activity along the highway resulting in extra vibration, and the presence of flyschoidal unitsBu çalışmanın amacı, kısa ve öz veri kaynaklı bir heyelan afeti tayin yöntemi geliştirmek ve değerlendirmektir. Bu amaçla uygulama arazisi olarak Asarsuyu su toplama havzası ve Bolu Dağı otoyol geçişi seçilmiştir. Bu çalışmada, uzaktan algılama ürünleri, jeolojik haritalar ve topografik haritalar, olmak üzere üç veri alanı kullanılmıştır. Hava fotoğrafları kullanılarak dört ayrı dönemin heyelan envanteri çıkarılmıştır. Arazi kullanım haritası için ise, uydu görüntülerinden yararlanılmıştır. Jeolojik ve topografik haritalardan ve uzaktan algılama ürünleri kullanılarak 13 ayrı parametre haritası üretilmiştir. Bu parametre bilgilerini bir veri tabanına aktarabilmek için, 25x25 metrelik bir ağ arazi üzerine oturtulmuştur. İki ayrı takım nokta belirlenmiştir. Bunlardan ilki kayan kütlelerin özelliklerini, diğeri ise kaymaya neden olan koşulları içermektedir. Bu noktalarda saklanan bilgiler, beş ayrı veri tabanına aktarılmıştır. Bunlardan kayan kütle ve kök hücre veri tabanları iki ana veri tabanını oluşturmaktadır. Diğer üç yardımcı veri tabanı ise, alansal (polystats), şekilsel (fuzzystats) ve foto-karakteristik veri tabanlarıdır. Veri tabanlarının üretilmesinden sonra heyelanlar hakkında ilk karar verme kuralları elde edilmiştir.İlk sonuçlar ışığında en basit ve ayrıntısız analizlerden başlayarak, en karmaşık istatistiksel yöntemlere kadar uzanan bir heyelan afeti tayin yöntemi izlenmiştir. En son olarak ise, göreceli hata tayin yöntemi kullanılmıştır. Bunların ışığında en makul ve gerçeğe en uygun yötemin mantıksal regresyon olduğu sonucuna varılmıştır. Heyelan afeti tayininin sonuçlarına gore, düşük nüfus yoğunluğu, bozulmamış arazi örtüsü, E-5 otoyoluna ile aktif fay hatlarına uzaklığı ve sağlam kaya birimleri ile Asarsuyu su toplama havzasının kuzey yamaçları çok düşük riskli afet alanı olarak belirlenmiştir. Güneybatı yamaçları, özellikle Bolu Dağı geçişi ise, E-5 yolunun yarmaları nedeniyle yok olan yanal destekler, aktif faylara olan yakınlığı, E-5 otoyolundaki yüksek trafik yoğunluğu ve fliş litolojisinin varlığı nedenyle çok yüksek riskli afet alanı olarak belirlenmiştir.Ph.D. - Doctoral Progra

Active shoreline changes of büyük menderes river delta in the last 50 years

The coastal face of Büyük Menderes River is characterized by a complex system of lagoons, inlets, lakes, natural levees, beach ridges and river promontories. The geomorphological aspects of this complex system had been studied by means of aerial photographs and archive topographical maps. Three different periods of dataset is used where the earliest set is dated as 1956-1963, the next as 1977-1980 and the most recent one as 1996. In addition to aerial photographic studies, field observations have been made in 77 different locations in summer of 2004. It is observed that the most active parts of this shoreline are the promontories of Büyük Menderes River. One active and one relict promontory (northern and southern deltas) are observed with two different river courses. Two large lagoons are located behind the beach ridges of the shoreline. The so called Dil Lake -a large Lagoon- lies in the north part of the active promontory and joined with 2 inlets to the Aegean Sea as observed on aerial photographs and in field surveys done in 2004. The other one known as Akköy Lagoon is located on the south of the active promontory and also contiguous to the relict one. In year 2004, the Akköy Lagoon has 3 main inlets. The major changes detected in the shoreline between the observed dates are concentrated in the closure of inlets, formation of new sand barriers, slight changes in the course of the sand beaches and in the shape of promontories. It is expectably observed that the active promontory continues to aggrade since 1956 to 2004 for 50 years. However, on the other hand, the ceased promontory after a certain aggradation until 1963 is degrading continuously as a result of the human control and change in the southern course of Büyük Menderes River

Filtering of satellite images in geological lineament analyses: an application to a fault zone in Central Turkey

Lineament extraction and analysis is one of the routines in mapping large areas using remotely-sensed data, most of which is the satellite images. In this study, we aimed to test different lineament extraction techniques including single band, multiband enhancements and spatial domain filtering techniques. A fast algorithm has been developed for time and cost limited surveys in an area with known dominant and/or any selected orientation of lineaments. During the study for single band analysis, histogram equalization and stretching, for multiband, Principal Components Analysis (PCA) and for spatial domain filtering Prewitt and Sobel filters are utilized. Furthermore, we have developed a new algorithm which consists of a combination of large smoothing filters and gradient filters, in order to get rid of the artificial lineaments which are out of interest and to determine discontinuous and/or closely spaced regional lineaments. The results are as follows; the number of lineaments and their total lengths are 218 285.3 km using the single band; 255 343.9 km in multiband enhancements, and 347 644.9 km in the combination of spatial domain filtering including our algorithm. The 59.17 per cent increase in the number of lineaments and the 126.04 per cent increase in the total lengths indicate that a combination of spatial domain filters is the most cost-time efficient algorithm in lineament analyses

A new method for automated estimation of joint roughness coefficient for 2D surface profiles using power spectral density

In this study, a new method for the objective and accurate estimation of the joint roughness coefficient (JRC) of surface profiles, which are extracted from terrestrial laser scanner point clouds, is proposed. The requirements of objectivity, accuracy, reliability, and suitability for automatic analysis have been the basic criteria in assessing the performance of the procedure for JRC estimation. The procedure to estimate the JRC value of a sample profile is based on a similarity measure, between the third-order polynomial function fits to the power spectral density in the spatial frequency domain of the sample surface profile and Barton's reference profiles. The procedure is tested on the one hundred and two digitized surface profiles found in the literature. Normal probability density distribution of estimation errors of the results show that the JRC estimation by the proposed method is more accurate and precise compared to the results from the three versions of the well-known and commonly used Z(2) method

A comparison of the GIS based landslide susceptibility assessment methods: multivariate versus bivariate

The purpose of this study is to evaluate and to compare the results of multivariate (logical regression) and bivariate (landslide susceptibility) methods in Geographical Information System (GIS) based landslide susceptibility assessment procedures. In order to achieve this goal the Asarsuyu catchment in NW Turkey was selected as a test zone because of its well-known landslide occurrences interfering with the E-5 highway mountain pass