The present work proposes the use of the statistical method of frequency ratio (RF) and the hierarchical analytical process (AHP) to obtain zoning maps of the landslide processes, determining the susceptible areas in the territory of the Cayambe canton located in the province of Pichincha in Ecuador. Statistical methods use sample data based on the relationship between landslides and causal factors, evaluating the combination of these data objectively. As results, it was identified that the analysis of the landslide indices according to the FR method and the AHP method, shows that the inclination of the slope and the exposure are the important factors in the analysis of the susceptibility of the territory. However, a separate analysis shows that, for the FR method, the stratigraphic genetic complex factor is the most relevant, while for the AHP method, the most important factor is the steepness of the slope. On the other hand, the analysis of the distribution of landslides by parish shows that rural parishes present a greater number of landslide processes. In this way, it is highlighted that the Cangahua rural parish has 42% of the total landslides identified in the canton. Followed by the parishes Santa Rosa de Cusubamba and San José de Ayora, together with 29% of the landslides.

The article presents study results of the land subsidence caused by groundwater exploitation in Hanoi, Vietnam. The study includes collection and analysis of data on geology, hydrology, soil properties and settlements observed at 10 monitoring stations as well as models of the time-dependent settlement. The calculated settlements are relatively close to actual monitoring data. The models were done for prediction of the land subsidence at 92 selected points by the finite element method. Prediction maps are made for prediction of the land subsidence in 2020 and 2030. Recommendations are proposed for potential zones of groundwater exploitation in Hanoi.

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Link for citation: Nechaev D.A., Strokova L.A. Assessment of karst-suffusion hazard of the Chayanda–ESPO oil pipeline in Yakutia. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 7, рр. 78-92. In Rus. The study is relevant due to the need to identify dangerous sections of oil and gas pipelines located in underdeveloped and sparsely populated areas, due to the development of dangerous geological processes. This study aims to assess the intensity and forecast the development of karst-suffusion processes within the pipeline route located in southern Yakutia, and to determine the most significant factors that activate this process. Methods: processing engineering and geological survey data, digitization of geological maps and decoding satellite images to build factor maps that affect the activation of the karst process: geological structure of the route; curvature, slope, surface exposure; map of surface drainage density and density of total tectonic fracturing. We created a map of the density of karst occurrences along the route according to the route survey and data from engineering and geological surveys during construction. We compiled a map of the susceptibility of the route territory to the development of karst-suffusion processes based on the Frequency Ratio method. Results. We carried out a description of the engineering and geological conditions of the pipeline route. To assess the karst-suffusion hazard of the pipeline route, calculations were made of the expected sizes of sinkholes in the base of structures using the method of G.M. Shakhunyants. Using the method of the ratio of particulars, the correlations between factors and foci of karst occurrences along the pipeline route were obtained. The susceptibility map developed on the basis of these results makes it possible to determine specific site boundaries for determining solutions for monitoring the development of the exogenous process and optimizing the pipeline operation processes. Therefore, the application of such methodology can be applied to other extended gas and oil pipelines located in difficult geological conditions.

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