Search

Landslides are one of the devastating geohazards that cause extensive socio-economic and environmental damages on local, regional, and global scales. Previous studies based on digital media sources have attracted attention to the high fatal landslide rate in Turkey, at a continental or global scale; however, the preparation of a comprehensive and long-term database for Turkey has been neglected until today. To examine this data gap, we present a new database of fatal landslide events resulting in fatalities from 1929 to 2019, which has been compiled using Turkish national and local printed and digital media reports, academic papers, disaster, and city annual reports. The fatal database of Turkey (FATALDOT) shows that, in total, 1343 people were killed in 389 fatal landslide events. The spatiotemporal distribution of the fatal landslides highlighted increasing trends with reference to two distinct hotspot zones throughout the Eastern Black Sea and Marmara Region, mostly around Istanbul megacity. Our results show that there has been a significant uniformity between the number of fatalities and fatal landslides triggered by anthropogenic and natural factors over the past decade, indicating an increasing dominance of human activities in fatality rates. Our findings also, for the first time, remarked the potential signatures of the economic crisis and political steadiness on fatal landslide trends. Nevertheless, we conclude that the increasing rate of anthropogenic disturbances in urban and mountainous areas, together with regional variances in topography and climatic setting, is essential in governing the pattern of fatal landslides. [ABSTRACT FROM AUTHOR]

This paper focuses on the evaluation of temporal and spatial propagations of impulse waves using 3D numerical simulation-based models for a potential landslide area in the Tersun Dam reservoir, Northeast Turkey. The topographical model was created using Stereo Lithography files, and a drift-flux model was used to simulate the landslides. The wave generation was simulated using the Reynolds-averaged Navier–Stokes equations. The Drift-Flux approach was selected, and a renormalization group-based k-ε turbulence model was used to create a fluid–solid coupled model. The results show that a 16.5-m impulse wave is created as a result of sliding material hitting the water at a velocity of 16.4 m/s. The wave will reach the opposite shore in 27.4 s, and the run-up height will reach up to 48.8 m. As the wave, with an average velocity of 11.6 m/s in the reservoir, propagates toward the dam body, its height will decrease, and a 3.7-m-high wave will hit the dam in 155 s. A validation analysis performed using empirical equations and laboratory model tests indicates small differences in the results. The main reason for these differences is that the evaluation of wave properties is independent of the type of mass movement in empirical methods. A proper stability analysis is required to have a better estimation of the volume and the velocity of the sliding mass. [ABSTRACT FROM AUTHOR]

This paper describes the cut slope stability problems of southern engineered slopes along 57 km long Mersin-Tarsus Motorway. While the northern slopes were slipping during and following construction, the stability problems occurred at southern slopes after heavy rains in December 2001. The most recent slope stability problem took place on chainage at the km 10+800 embankment on 9 April 2009. About 3.62 × 10 m soil materials have currently slipped at 60 different location. After the occurrence of slides, different remedial methods (reshaping slopes, soil improvements, etc.) have been applied to stabilize the slipped slopes. The slope stability studies were carried out using back analysis to determine the slope failure mechanisms and to estimate effective shear strength parameters. Pore water pressures increase following intense rainfall events and cause reduced resistance to shear strength at the engineered slopes. In addition, the affects of the static and dynamic parameters to analyse the state of the slope after excavation were investigated and possible remedies to improve the state (toe rockfill and retaining wall) were assessed for motorway slopes through determining the slope stability with water parameter and seismic loading, separately and together. The results of the stability analysis have exhibited that a good drainage system and retaining wall prevents the motorway slope slides. [ABSTRACT FROM AUTHOR]

The paper proposes a methodology for quantitative landslide risk assessment for regional-scale analysis. Each component of risk, i.e., hazard, vulnerability, and consequence analysis, is quantitatively assessed. The developed landslide risk assessment methodology is tested in Kumluca watershed, in Bartın, Turkey. Geographic information systems and remote sensing techniques are used to create landslide factor maps, to obtain susceptibility maps, hazard maps, elements at risk, and risk maps. Susceptibility maps are obtained by using a logistic regression model while adopting a grid-based mapping unit. In addition to spatial probability of occurrence of damaging events, landslide hazard calculation requires the determination of the temporal probability. Precipitation triggers the majority of landslides in the study region. The critical rainfall thresholds were estimated by using antecedent rainfalls and landslide occurrence dates based on Gumble Distribution approach. The elements at risk are extracted from existing digital cadastral databases and the vulnerabilities are obtained by adopting some generalization approaches. To conclude, quantitative risk maps were produced on a continuous scale where numerical values indicate the distribution of risk including the annual probability of expected losses in TL per pixel and the annual probability of life loss per pixel for property and life, respectively. For the considered case study, it is found that the annual probability of property loss is the highest for the provincial highway and the provincial road. The property loss map highlights that the annual expected loss to power network is medium. The annual probability of life loss map illustrates that the region surrounded by Kumluca town, Kızıllar, and Zafer villages have medium and high annual expected loss of population values, respectively. [ABSTRACT FROM AUTHOR]