Approved Plan - EXE230029

                                                 LANDSLIDE RISK MANAGEMENT
                                               Definition of Terms and Landslide Risk

              Risk Terminology          Description
              Acceptable Risk           A risk for which, for the purposes of life or work, we are prepared to accept as it is with no regard to its
                                        management. Society does not generally consider expenditure in further reducing such risks justifiable.
              Annual Exceedance         The estimated probability that an event of specified magnitude will be exceeded in any year.
              Probability (AEP)
              Consequence               The outcomes or potential outcomes arising from the occurrence of a landslide expressed qualitatively
                                        or quantitatively, in terms of loss, disadvantage or gain, damage, injury or loss of life.
              Elements at Risk          The population, buildings and engineering works, economic activities, public services utilities,
                                        infrastructure and environmental features in the area potentially affected by landslides.
              Frequency                 A measure of likelihood expressed as the number of occurrences of an event in a given time. See also
                                        ‘Likelihood’ and ‘Probability’.
              Hazard                    A condition with the potential for causing an undesirable consequence (the landslide). The description
                                        of landslide hazard should include the location, volume (or area), classification and velocity of the
                                        potential landslides and any resultant detached material, and the likelihood of their occurrence within
                                        a given period of time.
              Individual Risk to Life   The risk of fatality or injury to any identifiable (named) individual who lives within the zone impacted
                                        by the landslide; or who follows a particular pattern of life that might subject him or her to the
                                        consequences of the landslide.
              Landslide Activity        The stage of development of a landslide; pre failure when the slope is strained throughout but is
                                        essentially intact; failure characterised by the formation of a continuous surface of rupture; post failure
                                        which includes movement from just after failure to when it essentially stops; and reactivation when the
                                        slope slides along one or several pre-existing surfaces of rupture. Reactivation may be occasional
                                        (eg. seasonal) or continuous (in which case the slide is ‘active’).
              Landslide Intensity       A set of spatially distributed parameters related to the destructive power of a landslide. The parameters
                                        may be described quantitatively or qualitatively and may include maximum movement velocity, total
                                        displacement, differential displacement, depth of the moving mass, peak discharge per unit width, or
                                        kinetic energy per unit area.
              Landslide Risk            The AGS Australian GeoGuide LR7 (AGS, 2007e) should be referred to for an explanation of Landslide
                                        Risk.
              Landslide                 The classification, and volume (or area) of landslides which exist or potentially may occur in an area or
              Susceptibility            may travel or retrogress onto it. Susceptibility may also include a description of the velocity and
                                        intensity of the existing or potential landsliding.
              Likelihood                Used as a qualitative description of probability or frequency.
              Probability               A measure of the degree of certainty. This measure has a value between zero (impossibility) and 1.0
                                        (certainty). It is an estimate of the likelihood of the magnitude of the uncertain quantity, or the
                                        likelihood of the occurrence of the uncertain future event.
                                        These are two main interpretations:
                                        (i) Statistical – frequency or fraction – The outcome of a repetitive experiment of some kind like
                                            flipping coins. It includes also the idea of population variability. Such a number is called an
                                            ‘objective’ or relative frequentist probability because it exists in the real world and is in principle
                                            measurable by doing the experiment.




            February 2019



Document Set ID: 22532435
Version: 1, Version Date: 07/08/2023