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In the frame of the DAMAST (Dams and Seismicity) project, we deployed a dense high-fidelity seismological real-time network to investigate in detail the spatio-temporal seismicity distribution around the Enguri high dam, situated in the greater Caucasus in western Georgia. We aim at recording the weak seismicity in a 10 km distance around the dam structure. To lower the detection threshold by reducing the ambient background noise, we installed four seismic stations in shallow (ca. 20 m) and deep boreholes. From these stations, KIT1 with a depth of ca. 250 m is the deepest seismological station in Georgia. In this paper, we characterize the seismicity recorded by the local seismic network from October 2020 to July 2022. To have a better historical picture of the seismic activity, especially since the dam construction and initial operations, re-processing of the old seismological catalogs was carried out. This required digitizing the paper-only catalog copies prior to relocation. We finally obtain a uniform catalog for the Enguri region to characterize the seismicity and start investigating its possible relationship with the exploitation of the dam reservoirs. [ABSTRACT FROM AUTHOR]

The slake durability test device was primarily designed for argillaceous rocks (clay-bearing) such as shale, claystone mudstone, and marl by Franklin and Chandra (Franklin JA, Chandra R (1972) The slake-durability test. Int J Rock Mech Min Sci 9:325–341). Later, the International Society for Rock Mechanics standardized the test method (ISRM (2007) The complete ISRM suggested methods for rock characterization, testing, and monitoring, 1974–2006. In: Ulusay R, Hudson JA, compilation arranged by the ISRM Turkish national group, Ankara, Turkey). The slake durability test is conducted to assess the durability offered by argillaceous rocks to degradation (slaking) when subjected to wetting–drying cycles (WD cycles). However, in previous decades two, various researchers also have used this test to assess non-argillaceous rocks. In this paper, the effects of the WD cycles and rock lumps abrasion (RLA) on the degradation of argillaceous and non-argillaceous rocks during the slake durability test are investigated. To this end, some marls and limestones (as argillaceous and non-argillaceous samples, respectively) were collected from rock trenches along roads in Lorestan province, west of Iran. The mineralogical studies were performed by microscopic thin sections and X-ray diffraction analyses (XRD). Also, physico-mechanical tests, including porosity (n) and point load index (PLI), and slake durability tests up to 15 cycles were carried out to characterize the samples. Results indicated that the degradation of argillaceous samples [assessed using slake durability index (SDI)] during the slake durability test was remarkably affected by WD cycles. Besides, the RLA showed less effect on the degradation of these samples. WD cycles had a preventative role in the degradation of the non-argillaceous samples, and only the RLA was responsible for the degradation of these sample types. The findings show that clay minerals in argillaceous samples make them highly susceptible to degradation by WD cycles. Moreover, the absence of these minerals in non-argillaceous samples has caused their degradation to be independent of the WD cycles. According to simple regression analyses, there is a good correlation between the degradation of the argillaceous samples with their saturated-to-dry PLI ratio (PLIr). However, no significant correlation existed between degradation and PLIr of the non-argillaceous samples. Overall, the PLIr can be considered a low-cost, rapid, and precise indicator to assess the degradation of the argillaceous samples during the slake durability test. Highlights: The effect of the wetting-drying cycles (WD cycles) on the degradation of argillaceous and non-argillaceous rocks was investigated. The degradation of argillaceous samples during the slake durability test was remarkably affected by WD cycles The absence of clay minerals in non-argillaceous samples has caused their degradation to be independent of the WD cycles. There is a good correlation between the degradation of the argillaceous samples with their saturated-to-dry PLI ratio (PLIr). The PLIr can be considered a low-cost, rapid, and precise indicator to assess the degradation of the argillaceous samples during the slake durability test. [ABSTRACT FROM AUTHOR]

This paper compares the classification and prediction capabilities of decision tree (DT), genetic programming (GP), and gradient boosting decision tree (GBT) techniques for one-month ahead prediction of standardized precipitation index in Ankara province and standardized precipitation evaporation index in central Antalya region. The evolved models were developed based on multi-station prediction scenarios in which observed (reanalyzed) data from nearby stations (grid points) were used to predict drought conditions in a target location. To tackle the rare occurrence of extreme dry/wet conditions, the drought series at the target location was categorized into three classes of wet, normal, and dry events. The new models were trained and validated using the first 70% and last 30% of the datasets, respectively. The results demonstrated the promising performance of GBT for meteorological drought classification. It provides better performance than DT and GP in Ankara; however, GP predictions for Antalya were more accurate in the testing period. The results also exhibited that the proposed GP model with a scaled sigmoid function at root can effortlessly classify and predict the number of dry, normal, and wet events in both case studies. [ABSTRACT FROM AUTHOR]

This paper presents the performance of the latest version of the International Reference Ionosphere (IRI-2016) model for estimating the Total Electron Content (TEC) variations in the mid-latitudinal Turkish regions during low solar activity years (2015–2018). Moreover, TEC is estimated from dual-frequency Global Navigation Satellite System (GNSS) receivers operating in different regions of Turkey: Zonguldak (41.44 °N, 31.77 °E), Ankara (39.88 °N, 32.75 °E) and Antalya (36.88 °N, 30.66 °E). The diurnal, monthly and seasonal variations in the measured TEC are compared with the prediction of modelled TEC. The results reveal minimum variations in the diurnal TEC after midnight hours 21:00–24:00 Universal Time (UT = LT + 3 : 00 hrs ) and maximum TEC enhancement during the daytime from 9:00–15:00 UT (12:00–18:00 LT). The monthly mean TEC from measured and modelled estimation depicts the highest and lowest values in April and December during the years 2015–2018, respectively. Moreover, the low and high seasonal variations are observed in equinoxes and winter solstice, respectively. Furthermore, it is observed that IRI-2016 model underestimates the measured values, especially during the daytime (12:00–18:00 LT) at each station. The correlation coefficient between the measured and modelled TEC is found in the range (R = 0.81 – 0.85 ) during the years 2015–2018, which exhibits a high positive correlation over the regions. The model predicted TEC is showing a good agreement with measured TEC of the ionospheric dynamics over the regions, which manifests the radio signals accuracy over the mid-latitude regions, particularly Turkey. [ABSTRACT FROM AUTHOR]

This paper analyzes an institutional change in a large, Turkish public university, the Middle East Technical University (METU), by using an anomaly-based change model. The model explains change as an organizational response to anomalies caused by internal and external organizational conditions. The study used a qualitative case study design that included interviews with 51 individuals, and, analysis of institution-specific documents. Anomalies derived from the interview findings compared with a separate set of anomalies, devised from the document study, that are attributed to the strategic change agenda developed by the current president of the institution. The paper argues that human thinking and problem solving as well as organizational cognition and problem solving do proceed through existence and recognition of a problematic situation. So, anomalies are the ID cards of any major change in organizations in that they carry important information about where the organization comes from and where it should proceed to. Implications for the nature and management of change in higher education organizations are discussed. [ABSTRACT FROM AUTHOR]

Abstract  The paper reports an assessment of the engineering geological characteristics of the rock mass to be encountered between Mecidiye and Gazino stations on the new extension of the Ankara metro and the determination of appropriate support and excavation methods. The rock mass quality was estimated using the rock mass rating (RMR), geological strength index (GSI) and rock mass quality (Q) systems and the tunnel divided into sections. The RMR, Q and NATM systems were used to determine the support and excavation methods in these areas. The deformations and stress concentrations around each tunnel section were investigated and the interaction of the support systems with the rock mass was analyzed using finite element software. It is concluded that rock mass classification systems should be used in tandem with numerical tools, although it is emphasized that the estimation of rock mass properties is not an exact science and both rock properties and numerical models should be refined based on observations and the results of instrumentation installed during the construction of a tunnel. [ABSTRACT FROM AUTHOR]

Abstract  The paper presents the geotechnical properties along the route of the 9,325 m twin tunnel metro route in the Greater Municipality of Ankara. Convergence measurements taken during tunnel construction are presented and discussed. In addition, the convergence of the twin metro tunnels was analysed by means of a 2D plane strain finite element (FE) analysis. The FE model estimations and the field measurements are compared. [ABSTRACT FROM AUTHOR]