Distribution Characteristics Of Landslides Research Articles

Spatial distribution characteristics and influence factor analysis of landslides —case study of the Hanwang area in Qinba Mountains

The geological hazards of landslides in Hanwang Town, Ziyang County, Ankang City, Shaanxi Province, have emerged. Yet, the current understanding of the spatial distribution characteristics and influencing factors of landslides in this area remains unclear. Combining the results of remote sensing interpretation and field investigation, seven influencing factors, namely, elevation, slope direction, slope gradient, distance from rivers, distance from faults, engineering geologic lithology, and distance from roads, are selected for the study. The distribution characteristics of landslides in each influencing factor and the influence of the resolution of the Digital Elevation Model (DEM) on the results are statistically and analytically analyzed. Furthermore, two high-risk landslides within the study area were subjected to comprehensive analysis, integrating the findings from drilling and other field investigations in order to examine their deformation mechanisms. Based on this analysis, the following conclusions were derived: (1) 34 landslides in the study area, mainly small earth landslides, with a distribution density of 0.42/km2, threatening 414 people and property of about 55.87 million Yuan. (2)The landslides in the study area easily occur in the <400 ​m elevation range; the landslides are developed in all slope directions, the gradient is mainly concentrated in the range of 10°–40°, the distribution density of the landslides is higher in the closer distance from the river and the faults (0–200 ​m), the landslide-prone strata are mainly the softer and weaker metamorphic rocks, and the landslides are mainly around roads. (3) The resolution of the DEM should be selected based on the specific conditions of the study area, the requirements of the investigation, and the scale of the landslide. Opting for an appropriate DEM resolution is advantageous for understanding the patterns of landslides and conducting risk assessments in the region. (4) The Zhengjiabian landslide is a traction Landslide. The landslide body is a binary structure of gravel soil and slate weathering layer, and the damage process can be divided into three stages:①damage to the leading edge and stress release, ②continuous creep and cracking, ③rainfall infiltration and damage. The predominant slope material in the Brickyard landslide comprises clay, and the landslide is triggered by a combination of the traction effect resulting from the excavation at the slope's base and the nudging effect caused by the stacking load of the brick factory. Additionally, the Brickyard landslide exhibits persistent creep deformation. The study results provide a scientific basis for disaster prevention and mitigation in the Hanwang Township area.

Wide Area Detection and Distribution Characteristics of Landslides along Sichuan Expressways

Wide area landslide detection is a major international research hotspot in the field of geological hazards, and the integration of multi-temporal optical satellite images and spaceborne interferometric synthetic aperture radar (InSAR) appears to be an effective way to realize this. In this paper, a technical framework is presented for wide area landslide detection: (i) multi-temporal satellite optical images are used to detect landslides with distinguishable geomorphological features; (ii) Generic Atmospheric Correction Online Service (GACOS) assisted InSAR stacking is employed to generate annual surface displacement rate maps in radar line of sight using satellite SAR images from both ascending and descending tracks, which are in turn utilized to automatically detect active landslides from ground motion using hotspot analysis, and (iii) the distribution characteristics of the detected landslides are investigated by examining their relationships with topographic and hydrological factors. Three expressways in Sichuan Province, China—namely the Yakang (Ya’an-Kangding), Yaxi (Ya’an-Xichang), and Lushi (Luding-Shimian) expressways—and their surrounding regions (a total area of approximately 20,000 square kilometers) were chosen as the study area. A total of 413 landslides were detected, among which 320 were detected using multi-temporal satellite optical images, and 109 were detected using GACOS-assisted InSAR stacking. It should be noted that only 16 landslides were detected by both approaches; these landslides all exhibited not only obvious geomorphological features but also ground motion. A statistical analysis of the topographic and hydrological factors shows that of the detected landslides: 81% are distributed at elevations of 1000–2500 m, over 60% lie within the elevation range of 100~400 m, and 90% present with medium and steep slopes (20°~45°), and 80% are located within areas seeing an annual rainfall of 950~1050 mm. Nine landslides were found to pose potential safety hazards to the expressways. The research findings in this paper have directly benefitted the Sichuan expressways; equally important, it is believed that the technical framework presented in this paper will provide guidance for hazard mitigation and the prevention of transportation hazards in the future.

Susceptibility Assessment of Landslides in Alpine-Canyon Region Using Multiple GIS-Based Models

This study explores a comparative study of three susceptibility assessment models based on remote sensing (RS) and geographic information system (GIS). The Lenggu region (China) was selected as a case study. At first, a landslide inventory map was compiled using data from existing geology reports, satellite imagery, and coupling with field observations. Subsequently, three models were built to map the landslide susceptibility using analytical hierarchy process (AHP), fuzzy logic (FL) and certainty factors (CF). The resulting models were validated and compared using areas under the curve (AUC). The AUC plot estimation results indicated that the three models are promising methods for landslide susceptibility mapping. Among the three methods, CF model has highest prediction accuracy than the other two models. Similarly, the outcome of this study reveals that streams, faults, slope and elevation are the main conditioning factors of landslides. Especially, the erosion of streams plays a key role of the landslide occurrence. These landslide susceptibility maps, to some extent, reflect spatial distribution characteristics of landslides in alpine- canyon region of southwest China, and can be used for land planning and hazard risk assessment.

2011年4月11日福島県浜通りの地震で引き起こされた地すべり・表層崩壊の分布特性

2011年4月11日福島県浜通りの地震で引き起こされた地すべり・表層崩壊の分布特性

Consideration on the Mechanism of Landslides at Serpentine Belt.

The distribution characteristics of landslides in the serpentine belt were investigated. It was clear that the landslide occurred at the edge of the serpentine belt. The geological, mineralogical and soil mechanical causes of this phenomenon were considered. One is due to the geological reason that the talc and clorite are generated at the edge of serpentine belt by the hydrothermal alteration. Another is due to the soil mechanical reason that the shear strength of the talc and clorite is small.