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The origin of Neogene tectonic rotations in the Galatean volcanic massif, central Anatolia 总被引：1，自引：1，他引：0
A paleomagnetic study was carried out on Neogene volcanic rocks at 30 sites within the Galatean massif (40.4°N, 31.5°E) to
determine possible block rotations due to stress variations. Two phases of rotation could be characterized as the result of
Neogene volcanic activity. We suggest that the first stage of rotation was isolated in Early Middle Miocene calc-alkali rocks,
with a relative counterclockwise rotation of R ± ΔR = −20.2 ± 9.3° with respect to Eurasia. This accommodates the south-westward rotational collapse of the Western Anatolia
peninsula across a pole on the Bitlis suture. In the neotectonic period, on other hand, a relative clockwise rotation of R ± ΔR = 27.3 ± 6.4° with respect to Eurasia is predicted. In contrast to the uniform clockwise rotations, extremely large clockwise
rotations up to 264° are restricted in a narrow zone between two dextral faults. We believe that the second stage rotations
support the idea of individual microblock rotations due to deformation along the North Anatolian Fault zone. 相似文献
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Umut Gunes Sefercik Naci Yastikli Iulia Dana 《Journal of the Indian Society of Remote Sensing》2014,42(2):279-290
Three-dimensional (3D) spatial information is crucial for improving the quality of human life through urban planning and management, and it is widely utilized due to its rapid, periodic and inexpensive acquisition. In this context, extraction of digital surface and elevation models (DSM and DEM) is a significant research topic for space-borne optical and synthetic aperture radar (SAR) remote sensing. The DSMs include visible features on the earth’s surface such as vegetation, forest and elevated man-made objects, while DEMs contain only the bare ground. In this paper, using TerraSAR-X (TSX) high resolution Spotlight (HS) images, high-resolution interferometric DEM generation in a part of Istanbul urban area is aimed. This is not an easy task because of SAR imaging problems in complex geometry of urban settlements. The interferometric processing steps for DSM generation were discussed including critical parameters and thresholds to improve the quality of the final product and a 3 m gridded DSM was generated. The DSM-DEM conversion was performed by filtering and the quality of generated DEM was verified against a reference DEM from stereo photogrammetry with 3 m original grid spacing. The achieved root mean square error of height differences (RMSZ) varies from 7.09 to 8.11 m, depending on the terrain slope. The differential DEM, illustrates the height differences between generated DEM and the reference DEM, was generated to show the correlation between height differences and the coherence map. Finally, a perspective view of test area was created draping extracted DEM and a high-resolution IKONOS panchromatic image. 相似文献
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Investigation into regional thermal structure of the Thrace Region, NW Turkey, from aeromagnetic and borehole data 总被引：1，自引：0，他引：1
Z. Mümtaz Hisarli M. Nuri Dolmaz Mahmut Okyar Ali Etiz Naci Orbay 《Studia Geophysica et Geodaetica》2012,56(1):269-291
The aeromagnetic values over the study region are relatively uniform except for a few anomalies in the northeastern and southwestern
areas. Analyses of aeromagnetic data were performed in NW Turkey, in order to have a look into the subsurface regional thermal
structure of the region. For this purpose, power spectra, reduced to pole (RTP), and band-pass filtered anomalies were produced
using geophysical techniques. Band-pass filtered data were produced from the RTP aeromagnetic anomalies to isolate near surface
and undesired deep effects. Based on the aeromagnetic data interpretation, the thickness of the magnetized crust, named the
Curie Point Depth (CPD), in the study area lies between 9.7 and 20.3 km. The CPD estimates in the Thrace region of Turkey
indicate two shallow CPD (SCPD1 and SCPD2) zones (the Istranca Massif and the Saros Graben area). The deep CPD are located
within the Thrace Basin with sediment thickness of about 9 km. The corresponding heat flow map prepared from the averaged
thermal conductivities and thermal gradients from the CPD reveals the existence of one low heat flow zone (75 mW/m2) over the center of Thrace Basin, and two high heat flow zones over the Istranca Masif (100–125 mW/m2) in the northern side and Saros Graben (125–135 mW/m2) areas in the southern side of the Thrace Basin. 相似文献
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Mualla Cengiz Cinku Dieter Rammlmair Mümtaz Z. Hisarli Naci Orbay 《Studia Geophysica et Geodaetica》2009,53(4):475-494
Upper Cretaceous volcanic rocks were collected at 24 sites along the Pontides, N-NE Turkey, for rock magnetic and geochemical
studies. Rock magnetic and petrographic methods showed that the lavas are characterized predominantly by titanomagnetites
with a mixture of pseudo-single and multi-domain grains, whereas in tephrite single domain titanohematite was dominant. Measurements
of magnetic susceptibility and the geochemical properties on different volcanic rock types provide important knowledge about
the magnetic stability of the rocks. The magnetic properties are interpreted in terms of the composition, concentration, magma
generation. Tephrite and phonotephrites with the highest intensities (5200 mA/m) and high magnetic susceptibility values (2585
× 10−5), largest grain sizes and Fe/Ti values, showing minor or no alteration are the most magnetic stable samples in contrast to
dacites with the lowest intensity-magnetic susceptibility (520 mA/m − 573 × 10−5) and high alteration degree. The basanite samples show very low NRM (48–165 mA/m) but very high magnetic susceptibility (2906–3100
× 10−5) values suggesting the alteration of Fe-Ti minerals. It is shown that the magnetic properties of the basic to acidic rocks
show a systematic variation with magma differentiation and could be related to fractional crystallization. Major and trace
elements revealed that the lavas are compatible with complex magma evolution, with mineral phases of olivine+magnetite+clinopyroxene
in basic series, amphibole+ +clinopyroxene in intermediate rocks and plagioclase+clinopyroxene+biotite in acidic series. 相似文献
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Mehmet Sinan Özeren M. Namık Çağatay Nazmi Postacıoğlu A. M. Celal Şengör Naci Görür Kadir Eriş 《Geo-Marine Letters》2010,30(5):523-539
Potential tsunami waves were modelled on the basis of the morphology and geological setting of a late glacial submarine landslide localized in the north-eastern sector of the Sea of Marmara, using a three-dimensional algorithm with the purpose of assessing the future risk of tsunamogenic landslides in the region. The landslide occurred off the Tuzla Peninsula on the north-eastern slope of the Ç?narc?k Basin, the easternmost of the three deep Marmara basins. The mass movement appears to be related to the Main Marmara Fault that passes below the toe of the failed mass. Observations from earlier manned submersible dives suggest that the initiation of the slide was facilitated by secondary faults associated with the Hercynian orogeny and involved Palaeozoic shales dipping southwards towards the deep basin. Radiocarbon dating of core material, together with the well-dated Marmara sapropel above the chaotically mixed landslide surface, reveal that the latest landslide event occurred about 17 14C ka b.p. The uppermost scar of the landslide is found at 250 m and its toe at about 1,200 m below the present sea level. At the time of the slide, the Marmara Sea Basin was lacustrine, with its water level at ?85 m. In plan view the landslide has a distinctively triangular shape and the lateral extent of its toe is about 10 km. Multibeam bathymetric data indicate that the sliding motion probably occurred in two phases: a slower phase affecting the eastern part, characterized by an undulating surface, and a more rapid phase affecting the western part that possibly created tsunami waves. In the seismic sections, older failed slide masses can be clearly identified; these were probably displaced during marine isotopic stage 6 (～127–160 ka b.p.). The front of this buried material is located more than 1.5 km further south of the fault. We used a three-dimensional, Green’s function-based potential theory approach, rather than shallow-water equations commonly used in conventional tsunami simulations. The solution algorithm is based on a source-sink formulation and an integral equation. The results indicate that the maximum height of the tsunami in the Ç?narc?k Basin could have reached about half the average thickness of the sliding mass over a lateral extent of 7 km. Assuming an average thickness of 30 m for the landslide, and considering that the water level at 17 ka b.p. was at about ?85 m, the modelling shows that the maximum wave height generated by the slide would have been about 15–17 m. 相似文献
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Erkan Çelebi Muharrem Aktas Naci Çağlar Aşkın Özocak Mustafa Kutanis Necati Mert Zeki Özcan 《Natural Hazards》2013,65(3):2287-2310
On October 23, 2011, a magnitude of Mw 7.2 earthquake struck the Van province in eastern Turkey which caused approximately 600 life loss and 4,000 injured people. Although the recorded peak ground accelerations were relatively low (0.15–0.2 g) compared with that of other recent destructive Turkish earthquakes and the code-based design response spectrum, a large number of reinforced concrete buildings with 4–6 stories and non-engineered masonry buildings were either heavily damaged or collapsed in the region. Based on the post-earthquake technical inspections, the goal of this paper is to introduce major reasons for structural damages in the disaster area and to discuss these failures along with the approaches given in the design code which is renewed after August 17, 1999 Marmara Earthquake. Some remarkable lessons learned from earthquake-induced failures and damages specific to building construction techniques are presented in this paper. 相似文献
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Natural Hazards - Owing to its special geodynamic setting on the western extension of the North Anatolian Fault (NAF) and oceanographic setting between Mediterranean and the Black Seas, the Sea of... 相似文献