Land-use planning
Branch of physical planning that determines the means and assesses the values or limitations of various options in which land is to be utilised, with the corresponding effects on different segments of the population or interests of a community taken into account in resulting decisions.

Landslide
Downward or outward movement of slope (mass of rock, earth (soil) or debris) under the influence of gravity. Some authors prefer the term of ‘mass movement’. There are numerous classifications within the landslide literature considering various factors as mechanism, morphology, type of material or rate of movement: fall, topple, slide (rotational), slide (translational), lateral spreading, flow … Land-use planning can help to mitigate disasters and reduce risks by discouraging settlements and construction of key installations in hazard prone areas, control of population density and expansion, and in the siting of life lines such as service routes for transport, power, water, sewage and other critical facilities. Land-use planning involves mapping, analysis of data acquired, formulation of alternative land-use decisions and design of a long-range plan for different geographical and administrative scales.

Landslide Hazard
The probability of occurrence within a specific period of time and within a given area of a potentially damaging phenomenon. More specifically, landslide hazard expresses the annual probability of occurrence of a class of landslide (e.g. rock fall) of a given size which may occur in or travel or retrogress into the hazard class area. Quantifying hazard may also require the estimation of the velocity or intensity of the potential landsliding. Landslide hazard may be expressed in several ways: the number of landslides per annum per unit area of the hazard class area or per unit length of the source area (e.g. for a cliff or for road cuttings or fills), or the annual probability that landsliding will occur to affect a point within the hazard class area.

Landslide Risk
(a) For life loss, the annual probability that the person most at risk in the risk zone will lose his on her life taking account of the landslide hazard, and the temporal spatial probability and vulnerability of the person. (b) For property loss, the annual probability of the consequence (e.g. a 0.001 probability/annum of damage) or the annualised loss (e.g. /annum) taking account of the elements at risk, their temporal spatial probability and vulnerability.

Landslide Susceptibility
The propensity of the terrain to produce a slope failure or that a landslide may travel onto or retrogress into it. For an existing landslide, susceptibility expresses its capability to reactive. Susceptibility may also include a description of the magnitude (volume) of the potential or existing landslide and the state of activity.

Lead time
Period of a particular hazard between its announcement and arrival, also used for the mobilization of resources needed in relief operations.

Lifelines
Vital communications and essential services that are liable to be compromised in disaster. They include the transportation networks along which emergency vehicles and evacuees will travel, main utility corridors for the distribution of electricity and water, and the medical assistance infrastructure.

Likelihood
Conditional probability of an outcome given a set of data, assumptions and information. Also used as a qualitative description of probability and frequency (Fell et al., 2005).

Limit
In relation to level of risk, that level which, when exceeded, is unacceptable. Higher risks cannot be justified except in extraordinary circumstances (typically where the continuation of the risk has been authorised by government or a regulator in the wider interests of society).

Loss
Any negative consequence, financial or otherwise; a reduction in the value of pre-existing resources (part of the costs experienced as the result of a hazard occurrence).

BACK TO GLOSSARY