Landslide Hazard Report_compressed

Specialists in transport geotechnics

Examples of Qualitative measures and risk from AGS 2007 used to inform the decision process
are presented below are presented below in table 1 and 2. A risk matrix used to inform
“Qualitative Risk” it presented in Table 3. Risk Level implications outlined in Table 4.
   Table 1: Qualitative Measures of Likelihood

                                                                                               Approximate
  Level          Descriptor           Description                                              Annual
                                                                                               Probability
  A              ALMOST CERTAIN       The event is expected to occur over the design life
                                                                                                    10-1
                                      The event will probably occur under adverse
  B              LIKELY                                                                             10-2
                                      conditions over the design life
                                      The event could occur under adverse conditions over
  C              POSSIBLE                                                                           10-3
                                      the design life
                                      The event might occur under very adverse
  D              UNLIKELY                                                                           10-4
                                      circumstances over the design life
                                      The event is conceivable but only under exceptional
  E              RARE                                                                               10-5
                                      circumstances over the design life
                                      The event is inconceivable or fanciful over the design
  F              BARELY CREDIBLE                                                                    10-6
                                      life


  Table 2: Qualitative Measures of Consequences To Property

  Level          Descriptor           Description
                                      Structure(s) completely destroyed and/or large-scale damage
  1              CATASTROPHIC         requiring major engineering works for stabilisation. Could cause at
                                      least one adjacent property major consequence damage.
                                      Extensive damage to most of structure, and/or extending beyond site
  2              MAJOR                boundaries requiring significant stabilisation works. Could cause at
                                      least one adjacent property medium consequence damage.
                                      Moderate damage to some of structure, and/or significant part of site
  3              MEDIUM               requiring large stabilisation works. Could cause at least one property
                                      minor consequence damage.
                                      Limited damage to part of structure, and/or part of site requiring
  4              MINOR
                                      reinstatement stabilisation works.
  5              INSIGNIFICANT        Little damage.


  Table 3: Qualitative Risk Analysis Matrix

          Likelihood                                           Consequence to
                                                                  Property
                      Approx.           1:             2:            3:               4:             5:
                      Annual
                     Probability   Catastrophic      Major          Medium          Minor       Insignificant
  A – Almost
                          10-1         VH             VH               VH             H            M/L
  Certain
  B - Likely              10-2         VH             VH               H              M              L
  C - Possible            10-3         VH             H                M              M              L
  D - Unlikely            10-4          H             M                L              L             VL
  E - Rare                10-5         M               L               L              VL            VL
  F - Barely
                          10-6          L              VL              VL             VL            VL
  Credible




10 May 2022                           CGC-SR-2022-011-R01-Rev01                                           Page 5