Slope Stability Assessment Using Trigger Parameters and SINMAP Methods on Tamblingan-Buyan Ancient Mountain Area in Buleleng Regency, Bali

• Published in: Geosciences (Basel) 2017-12, Vol.7 (4), p.110
• Main Authors: Sinarta, I, Rifa’i, Ahmad, Faisal Fathani, Teuku, Wilopo, Wahyu
• Format: Article
• Language: English
• Subjects: Accuracy; ancient mountain area; Area; Earth science; Geological structures; Groundwater; Groundwater potential; hazard scale; Hazards; Hydraulic conductivity; Inclination; Internal friction; Landslides; Literature reviews; Mapping; Mathematical models; Methods; Model accuracy; Mountain regions; Parameters; Rain; Rainfall; Seismicity; SINMAP; Slope stability; Soil; Soil dynamics; Soil mapping; soil movement mapping; Soil stability; Soil water; Soil water movement; Soils; Stability analysis; trigger parameter; Water absorption; Weathering
• ISSN: 2076-3263; 2076-3263
• DOI: 10.3390/geosciences7040110

The mapping of soil movement was examined by comparing an extension of the deterministic Soil Stability Index Mapping (SINMAP) method, and an overlay method with trigger parameters of soil movement. The SINMAP model used soil parameters in the form of the cohesion value (c), internal friction angle (φ), and hydraulic conductivity (ks) for the prediction of soil movement based on the factor of safety (FS), while the indirect method used a literature review and field observations. The weightings of soil movement trigger parameters in assessments were based on natural physical aspects: (1) slope inclination = 30%; (2) rock weathering = 15%; (3) geological structure = 20%; (4) rainfall = 15%; (5) groundwater potential = 7%; (6) seismicity = 3%; and (7) vegetation = 10%. The research area was located in the Buleleng district, in particular in the ancient mountain area of Buyan-Tamblingan, in the Sukasada sub-district. The hazard mapping gave a high and very high hazard scale. The SINMAP model gave a validation accuracy of 14.29%, while the overlay method with seven trigger parameters produced an accuracy of 71.43%. Based on the analysis of the very high and high hazard class and the validation of the landslide occurrence points, the deterministic method using soil parameters and water absorption gave a much lower accuracy than the overlay method with a study of soil motion trigger parameters.