10 Mass Wasting

A landslide economic risk map shows the potential annual cost of landslide damage throughout a region. Risk maps combine the probability information from a landslide hazard map with an analysis of all possible consequences . Landslide susceptibility maps ranks slope stability of an area into categories that range from stable to unstable.

Susceptibility maps show where landslides may initiate in future, but the “future” here is not connected to a time period, such as the next day or the next 5 years or 500 years. It only indicates the stability status of a slope under the analysed geo-environmental conditions, irrespective of a time of any landslide to occur. Many susceptibility maps use a colour scheme that relates warm colours to unstable and marginally unstable areas and cool colours to stable areas. The word mudflow can be confusing as, for example, in newspaper reports or in other languages, it is often used as a generic term to mention any type of rapid flow of concentrated water-sediment mixtures. In terms of cascading effects, a mudflow entering the hydrographic network may be the cause of a debris flow downstream. The passage of the earthquake waves through a granular material such as a soil can induce a process termed liquefaction, in which the shaking causes a reduction in the pore space of the material.

A landslide hazard map can be prepared early in the planning study and developed in more detail as the study progresses. It can be used as a tool to help identify land areas best suited for development by examining the potential risk of landsliding. Furthermore, once landslide susceptibility is identified, investment projects can be developed which avoid, prevent, or substantially mitigate the hazard.

Planners need to understand what effects development activities may have on this balance of forces. For example, placing a fence around a field is not going to produce a landslide, nor will it prevent one. This increased susceptibility may not be immediately apparent since there may be a lag time before this is evident.

These processes can be much more serious in mountainous areas in which the seismic waves interact with the terrain to produce increases in the magnitude of the ground accelerations. The maximum acceleration is usually seen at the crest of the slope or along the ridge line, meaning that it is a characteristic of seismically abc finance many la triggered landslides that they extend to the top of the slope. The most widely used classification scheme divides landslides into different types according to the material being moved and type of movement . Speed of movement and amount of water mixed with the material are secondary parameters defining some landslide types.

The term “landslide” encompasses events such as rock falls, topples, slides, spreads, and flows. In the absence of bedrock and slope steepness maps, the landslide inventory map can be used to produce an analytical map suitable for representing landslide activity in an area. An isopleth map of landslide frequency is recommended for this purpose.

The permafrost is ubiquitous in the arctic tundra, but less frequently found in alpine tundra sites, as alpine landscapes are more diverse and the summers are warmer. During spring, the thawing of the soil starts from the surface down, gradually releasing the vegetation from the grip of the frozen soil. There is usually an overlap between snow melt and the thawing of the soil, especially in undulating landscapes.