Türkiye Jeoloji Bülteni

Abstract: Structural data obtained from fault surfaces in the Bozburun Peninsula, southwest Türkiye indicate that the previously known active normal faults are indeed strike-slip structures. The configuration of left- and right-lateral strike-slip segments and lineaments observed from high-resolution satellite images, plus the evaluation of available focal mechanism solutions of the earthquakes having less than 30 km depth around Bozburun Peninsula, show that the study area is under influence of the left-lateral Ptolemy-Pliny-Strabo Fault Zone.

Abstract: Western Anatolia is a well-known continental extension province in the world. The most distinctive structural elements of the region are E-W trending grabens. The Alaşehir Graben forms the boundary between the northern and central parts of the Menderes Massif. It trends E-W from Ahmetli to Turgutlu and NW-SE from Salihli to Alaşehir. This paper documents the outcomes of field work along the southern margin of the Alaşehir Graben between the Salihli and Alaşehir areas.The tectono stratigraphy of the southern margin of the Alaşehir Graben is divided in the footwall and hanging wall of the Alaşehir detachment fault. The footwall comprises the Bayındır and Bozdağ Nappes and the syn-extensional Salihli granitoid intruding the Bayındır Nappe. The hanging wall consists of the Çine Nappe and Neogene-Quaternary sedimentary rocks, and Miocene fills tectonically overlying the Çine Nappe, which is above the Alaşehir detachment fault in the Alaşehir area. Structural data show three types of master fault sets, including (i) the low-angle Alaşehir detachment fault, which is composed of cataclastic rocks; (ii) low-angle normal faults, which are devoid of any cataclastic rocks;and (iii) Plio-Quaternary high-angle normal faults cutting them. Two different low-angle normal faults were coevaland active during the Miocene, and low-angle normal faults were synthetic and antithetic faults of the Alaşehir detachment fault. Their initial position was high-angle and the original position had 55°-75° dip during the Miocene.In the Salihli and Alaşehir segments, several major fold geometries are defined in the footwall and hanging wall ofthe Alaşehir detachment fault. The fold axis is NE-trending and plunges mainly northeast in the Salihli segment inthe footwall of the Alaşehir detachment fault. The other is ~ E-W-trending and plunges mainly west in the Alaşehir segment in the footwall and hanging wall of the Alaşehir detachment fault. They are associated with extensional structures formed by layer-parallel shortening during the Miocene. The Alaşehir detachment fault, as indicated bythe difference in fold axes between the Salihli and Alaşehir segments, was cut and back-rotated by Plio-Quaternary high-angle normal faults and tilted to the south.

Abstract: On 17 March 2005, a large and complex landslide occurred west of Koyulhisar (Sivas, Turkey). This landslide, mostly comprising debris derived from volcanic rocks and mud flow, moved over the Kuzulu settlement area in the valley in a very short time and 15 people were killed. The Kuzulu landslide zone is not a simple mass movement limited to a single movement. Instead, complexities are introduced by the regional topographic structureand location of the crown and heel zone so that at least 4 other large flow movements occurred in this region between 17 March 2005 and August 2007. One of the most important factors initiating and accelerating this landslide hasbeen the influence of surface and groundwater seep age from melting snow. This seepage has followed the densepattern of discontinuities and normal fault planes observed in and around the crown region. These waters saturated the profoundly altered volcanic bedrocks with water, and as a result, a slip surface developed between the underlying limestone and weathered volcanic rocks. This was responsible for the catastrophic mass movement.To correctly interpret the causes and consequences of mass movements, where the movement speeds and directions can be monitored in detail using the advanced technological tools available today, detailed geological mapping is essential. There are currently differing interpretations of the development and triggering factors responsible for the Kuzulu landslide. This is primarily because the geological and tectonic structure of the landslide zone and its surroundings have not hit her to been investigated in the necessary detail.In this study, a detailed new geological map revealing the basic geological features of the region has been compiled and the characteristics of the landslide re-evaluated for comparison with previous studies. With the help of Digital Elevation Model (DEM) maps created from the satellite images of the Kuzulu Landslide area before and after the landslide, a total volumetric movement of 10.367.766 m3 is estimated to have occurred. We calculate that anet 9,372,880 m3 of material flowed from the area within the landslide boundary. Any assessments of ground suitable for settlement with a view to urban development and planning requires aproper understanding of the geomorphological structure of the surrounding region and the engineering geologicalproperties of the ground. The fact that Koyulhisar district centre is located both in the immediate vicinity ofan active fault zone such as KAFZ and on an active landslide area emphasises this issue. Detailed geological, geomorphological, landslide susceptibility, hazard and risk maps are of great importance to prevent / mitigate the damaging consequences of earthquakes and the landslides that they may be motivated

Abstract: The Tauride fold-thrusts belt has formed under ~S–N convergence between the Africa and Eurasian platessince Cretaceous time. This movement also resulted in the development of the complex tectonic structure known asthe Isparta Angle. In the Neogene period, the western and central Taurides and the inner part of the Isparta Angle became overlain by marine sedimentary basins (Antalya Basin Complex).The Manavgat Basin is one of these marine basins, and unconformably rests on the Tauride in the north. Basically, the Manavgat Basin has a sedimentation thickness of more than 1 km from the Early Miocene to Pliocene.  Hence, it is expected to keep the geological records regarding the crustal deformation, besides the lithostratigraphic records during this time. Lithostratgraphically, seven basic units have been identified in the Manavgat Basin. These are, in line with previous studies; 1) Tepekli Formation (Burdigalian-E. Langhian), 2) Oymapınar Limestone (G.Burdigalian-Langhian), 3) Çakallar Breccia (Langhian), 4) Geceleme Formation (G. Langhian-Serravalian), 5)Karpuzçay Formation (G. Langhian-Tortonian), 6) Pliocene units (Yenimahalle and Kurşunlu formations), and 7)Belkıs Conglomerate (Quaternary).Biosamples were collected from two different measured sections of the Karpuzçay Formation, and the age of the formation was determined. These show that the Karpuzçay Formation was deposited in a deep marine outer neritic bathyal environment from the Late Langhian to Tortonian. In addition to lithostratigraphic features, structural elements forming the Manavgat Basin were also studied, and the Tortonian aged Çardakköy Fault was described forthe first time in this study.As a result, the presence of two different tectonic regimes in the region was determined. Accordingly, theManavgat Basin developed under the influence of an extensional tectonic regime before the Tortonian, and of acompressional system during the post-Tortonian. This study indicated that N-S directional convergence between Eurasia and Africa and the kinematics of the fragmented subducted plate under the Isparta Angle should be reevaluated based on these paleostress phases.

Abstract: Kocabaşlar geothermal field is located in Çanakkale province in northwestern Türkiye. A well was drilledto a depth of 650 m with a temperature of 46 °C. There is also a geothermal spring with a temperature of 38.1°C. The objective of this study was to model the Kocabaşlar geothermal field for the first time using an unmannedaerial vehicle (UAV) equipped with a dual camera to capture high-resolution thermal infrared (TIR) and visible(RGB) images. The UAV survey was conducted on January 6, 2023, when the air temperature was low and themeteorological conditions were favorable for image acquisition. The flight altitude was 40 m above ground level, andthe flight speed was 2.5 m/s. Image front and side overlaps were 80% and 70%, respectively. As a result of processinga total of 1718 TIR and RGB images, a high-resolution TIR orthophoto (5.25 cm/pixel), an RGB orthophoto (1.37cm/pixel), and a digital surface model (5.47 cm/pixel) were generated. The generated images were visualized in Geographic Information Systems software. The surface temperature in the geothermal field varied between 6 °C and38 °C. The Kocabaşlar geothermal field will be monitored for an extended period using UAV technology in order tocontribute to the development and sustainability of the utilization areas for geothermal energy.

Abstract: After a significant earthquake, Earthquake Research Commissions are established in the Grand National Assembly of Türkiye in order to help heal the wounds of the earthquake quickly, to reveal problem areas, to determine solutions that may be suggested, and to carry out earthquake-related studies. Starting from the first commission established in 1962, Earthquake Research Commissions were established eight times under different names in 1966,1997, 1999, 2010, 2020 and 2023. In addition to these, earthquake-related research commissions were established 4 times in the Senate of the Grand National Assembly in 1962, 1976, 1977 and 1978. It is equally important tomake findings and suggestions in the commission reports, as well as to follow them up and check whether they areimplemented. In order for the recommendations to be implemented, they must be legally binding. For this reason,it is important that the Grand National Assembly has the duty to put in practice the opinions and suggestionsstated in the reports of the Parliamentary Earthquake Research Commission and to make the proposed legislative changes. It will make significant contributions to Türkiye`s efforts to reduce earthquake risks if all political partiesin the Parliament work together and follow up on the proposals made in the reports, put their suggestions regarding legislative regulations on the agenda of Parliament as soon as possible and enact them, and ensure their implementation by checking whether their suggestions are implemented.The purpose of this article is to provide information about the Parliamentary Earthquake Research Commissions and reports prepared by these commissions that have been established from past to present, as well as to contribute to the development of recommendations and studies on reducing earthquake risks and to guide the commissions to be established in the future.