Jeodezi

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Browsing Jeodezi by Subject "Earthquakes -- Karlıova -- Turkey."

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    Investigation of post seismic deformation in Karlıova (Turkey) inferred from InSAR analysis
    (Thesis (M.S.) - Bogazici University. Kandilli Observatory and Earthquake Research Institute, 2013., 2013.) Horasan, Koray.; Doğru, Aslı.
    Interferometric Synthetic Aperture Radar is a new technique used in investigating the deformations occurring on the earth surface. By its capability of providing much broader domain coverage as compared to any other available techniques, geologists are using the interferometric synthetic aperture radar technique in many areas of their research and primarily crustal deformation. The purpose of this study is to observe the post-seismic impacts using the interferometry technique. In line with this purpose, the effects of deformations resulting from post-seismic impacts of earthquakes have been analyzed with the interferometric synthetic aperture radar technique. The region Karlıova was chosen as the study area. Karlıova-Bingöl-Erzincan triangle is located in the junction of the two most important transform faults: the North Anatolian Fault (NAF) and the East Anatolian Fault (EAF). The area between that two transform faults is a place where KDGB and KB-GD trending cross-fault systems is developed. Therefore, it is the region of the highest concentrations of the active faults in Turkey. The earthquakes that occurred in this region between 2005-2008 were examined in detail. With this study using the InSAR technique, for two separate earthquakes (10.12.2005 Mw=5.2 Depth:18 km and 26.08.2007 Mw=5.1 Depth:5km), a deformation in the direction of the satellite view of 56 mm during 2005-2006 and 140 mm during 2006-2008 has been determined respectively. In the interferograms generated by using the radar images in the C-band, one fringe theoretically corresponds to a deformation of half the radar wavelength. Therefore, deformations less than 28 mm in the area cannot be determined by the InSAR technique. The SAR data differ from the GPS data in time. During this time range, 17 earthquakes of moderate magnitude have also occurred in the area. The results differ from each other significantly since InSAR measurements contain post-seismic deformation while GPS observations do not. The spatial density of GPS sites is limited. Moreover, noisy interferograms due to atmospheric signal, and phase unwrapping errors affects the accuracy assessment and interpretation of the results.
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    North Anatolian and East Anatolian faults beyond Karlıova in the east
    (Thesis (M.S.) - Bogazici University. Kandilli Observatory and Earthquake Research Institute, 2021., 2021.) Elvanlı, Müfide.; Doğru, Aslı.
    The vicinity of Karliova, located at the intersection of two major fault systems in Turkey, is a seismically active region with a tectonically complex structure, however; there is little information about the east of Karliova, to what extent in the east the seismic activity continues. Investigating the possible extensions of the North Anatolian Fault (NAF) and the East Anatolian Fault (EAF) to the east of Karliova is therefore significant target to verify if there is a strain accumulation and therefore unknown earthquake hazard in the region. In this study, possible extensions of the NAF and the EAF in the east of Karliova were investigated using GPS slip rates. In this context, historical and instrumental period earthquakes had been compiled to identify potential indications for the possible extensions of the NAF and the EAF in the east of Karliova. With the focal mechanism solutions, it has been observed that the tectonics of this particular region is dominated by mostly strike slip structures. Fault information in previous studies conducted in the region was compiled to locate of potential eastern extensions to be used in the analysis. Also, the all-available GPS stations were homogenously combined (CORS-TR and campaign-based GPS measurements) to achieve the best possible station coverage to characterize tectonic surface deformation in the region. Using combined GPS data, Arctangent profiling analysis and block modeling analysis were performed to determine the location and movement of the potential extensions of the NAF and the EAF. The results of the analysis have shown that there is a strike slip faulting activity in the east of Karliova suggesting continuation of the NAF and the EAF in the east. The NAF extends ~ 170 km southeast of Karliova, by the slip rate of about 10.3 mm/y. The EAF extends ~ 180 km northeast of Karliova, by the slip rate of about 5.8 mm/y. For both fault systems, slip rates drastically decrease to the east of Karliova, down to the half of their slip rates in the west.