Characteristics of landslides induced by a debris flow at different geology with emphasis on clay mineralogy in South Korea

Abstract

Landslides induced by debris flow have been discussed in relation to the geotechnical properties of soil developed on bedrock, together with an emphasis on the importance of mineralogy comprising precursor soils. Three areas composed of different types of geology were compared to relate landslide with soil compositions: Precambrian gneiss (Jangheung area), Jurassic granite (Sangju area), and Tertiary sedimentary rocks composed of shale and mudstone (Pohang area) in Korea. X-ray diffraction for mineral identification and quantitative analysis, Scanning Electron Microscope for observation of microtexture, and laser size analysis for very fine particles ranging from micrometer were performed, with conventional measurements of particle size, porosity, density, permeability, and consistency for the soils. Soils at landslide sites containing a large amount of finer particles have higher uniformity and gradation coefficients, but lower consistency than those at non-landslide sites. Landslide areas are characterized by higher porosity and lower density. Soil from the gneiss area shows a high plasticity index while that of mudstone has high water content. Main clay minerals contained in soils of the sites where landslides took place are illite, chlorite, kaolinite, and montmorillonite. Mineralogical information on the constituents and microtexture of soils aids in better understanding the causes and patterns of landslide, together with mechanical properties of soils.

Effects of Rainfall Intensity, Soil Slope, and Geology on Soil Erosion in Korea

“…The supply of fine particles to dams and rivers induced by soil erosion causes a critical turbidity composed of suspended matters over a long period. It was shown that landslides induced by debris flow in Korea are commonly related to the geotechnical properties and clay mineralogy of precursor soils developed on bedrock [1]. This study aims to elucidate the importance of geological characteristics, soil slope, and rainfall intensity in relation to soil erosion.…”

The Ecological Perspective of Landslides at Soils with High Clay Content in the Middle Bogowonto Watershed, Central Java, Indonesia

“…Clay had characteristics of swelling, sensitive to humidity, and hydrous [7]. e small initial slip of clay might trigger large landslides that covered huge area [8].…”

Uncertainty Reduction of Unlabeled Features in Landslide Inventory Using Machine Learning t-SNE Clustering and Data Mining Apriori Association Rule Algorithms

“…As landslides occurred on terrain contain clays (mud rocks) [22], band ratio 7/5 was applied to distinguish argillic from nonargillic materials [23].…”