/pdf/landslide-inventory-maps-new-tools-for-an-old-problem-wkxin2jqxg.pdf

Landslide inventory maps: New tools for an old problem

Heavy metal pollution in the environment and their toxicological effects on humans

Spatial data for landslide susceptibility, hazard, and vulnerability assessment: An overview

Field data are used to study the size distribution of bedload in paved gravel-bed streams. Similarity analysis yields the results that all grain size ranges are of approximately equal transportability when the critical condition for breaking the pavement is exceeded. This result is only approximately correct due to deviations from similarity. However, it is adequate to justify development of a method for calculating total bedload, which requires only the subpavement median grain size rather than the size distribution. A method for calculating bedload size distribution that accounts for deviation from similarity is also developed.

Closure of "Bedload and Size Distribution in Paved Gravel-Bed Streams"

http://www.un-spider.org/sites/default/files/Stumpf%20and%20Kerle%202011.pdf

Object-oriented mapping of landslides using Random Forests

Despite the importance of landsliding in routing sediment through mountainous drainage basins, few studies have documented landsliding rates over extended time and space scales. We have investigated landsliding in surficial material in the Queen Charlotte Islands using a large inventory of events, derived from aerial photography, covering an area of 166.7 km 2 . The mean erosion rate for shallow landsliding is 0.10 mm·a -1 , which is at the upper end of shallow landsliding rates observed in the Pacific Northwest and coastal British Columbia, but several orders of magnitude lower than rock-based landsliding rates reported in the literature. Probability distributions for landslide area and volume are somewhat convex in form. Flattening of the curve found at low magnitudes may be due to sampling bias or physical mechanisms inhibiting failure, and the steepening for high values may exist because the sampling period is not long enough to adequately represent large events. Landslides generally initiate on hillslope gradients greater than 0.50-0.60. The largest numbers of landslides occur on south- to southwest-facing slopes and east- to northeast-facing slopes. Most events occur on concave and straight hillslopes in upper-slope positions. Landsliding rates were found not to be af - fected by rock type. Hillslopes in the Queen Charlotte Islands are often mantled by weathered Quaternary deposits and, hence, landsliding events are not directly controlled by weathering of bedrock. About 31% of landslides identified in this study deposited material in stream reaches, with about 83% of these landslides deposited in reaches with gradients between 3% and 10%. Resume : Malgre la grande contribution des glissements de terrain a acheminer des sediments a travers des bassins de drainage montagneux, peu d'etudes ont documente les taux de glissements de terrain sur une longue periode de temps et sur de grandes superficies. Nous avons fait des recherches sur des glissements de materiaux de surface dans les iles de la Reine-Charlotte en utilisant un grand inventaire d'evenements tires de photographies aeriennes couvrant une re-

Sediment transfer by shallow landsliding in the Queen Charlotte Islands, British Columbia

A resurgence of interest in landscape evolution has occurred as computational technology has made possible spatially and temporally extended numerical modelling. We review elements of a structured approach to model development and testing. It is argued that natural breaks in landscape process and morphology define appropriate spatial domains for the study of landscape evolution. The concept of virtual velocity is used to define appropriate timescales for the study of landscape change. Process specification in numerical modelling requires that the detail incorporated into equations be commensurable with the particular scale being considered. This may entail a mechanistic approach at small (spatial) scales, whereas a generalized approach to process definition may be preferred in large-scale studies. The distinction is illustrated by parameterizations for hillslope and fluvial transport processes based on scale considerations. Issues relevant to model implementation, including validation, verification, calibration and confirmation, are discussed. Finally, key developments and characteristics associated with three approaches to the study of landscape modelling: (i) conceptual; (ii) quasi-mechanistic; and (iii) generalized physics, are reviewed.

/pdf/numerical-modelling-of-landscape-evolution-geomorphological-eg048kvbpv.pdf

Numerical modelling of landscape evolution: geomorphological perspectives

Extensive landslide inventories are often utilized for hazard assessment studies and when investigating medium- to long-term evolution of alpine terrain. The predominant methodology for collecting these databases is aerial photographic interpretation, which can be time-consuming and expensive. Earlier work has demonstrated that spectral response patterns for satellite images, when used alone, are unreliable at detecting most types of landslides. Principal difficulties are related to inadequate image resolution and spectral methods of classifying image data that are not sensitive to the characteristics that identify landslide features such as their shape and topographic expression. This study in the Cascade Mountains of coastal British Columbia attempts to overcome the latter problem through image segmentation and the use of geomorphometric data derived from a digital elevation model (DEM). Image segmentation involved grouping pixels into discrete objects based on similarities and differences in their refl...

Detecting translational landslide scars using segmentation of Landsat ETM+ and DEM data in the northern Cascade Mountains, British Columbia

An automated approach to identifying landslides using a combination of high-resolution satellite imagery and digital elevation derivatives is offered as an alternative to aerial photographic interpretation. Previous research has demonstrated that per pixel spectral response patterns are ineffective in discriminating mass movements. This technique utilizes image segmentation and digital elevation data in order to identify mass movements based not only on their reflectance but also on their shape properties and their geomorphic context. Dividing the classification by process into debris slides, debris flows, and rock slides makes the method far more useful than methods that group all mass movements together. A hierarchical classification scheme is utilized to eliminate areas that are not of interest and to identify areas where mass movements are probable. A supervised classification is then conducted using spectral, shape, and textural properties to identify failures that were greater than 1 ha in area. The resulting accuracy was 90 percent for debris slides, 60 percent for debris flows, and 80 percent for rock slides.

Yvonne Martin

Papers

Sediment transfer by shallow landsliding in the Queen Charlotte Islands, British Columbia

Numerical modelling of landscape evolution: geomorphological perspectives

Detecting translational landslide scars using segmentation of Landsat ETM+ and DEM data in the northern Cascade Mountains, British Columbia

High Spatial Resolution Satellite Imagery, DEM Derivatives, and Image Segmentation for the Detection of Mass Wasting Processes

Evaluation of bed load transport formulae using field evidence from the Vedder River, British Columbia