Response to Information Request - MCU12/0184

                                  AUSTRALIAN GEOGUIDE LR7 (LANDSLIDE RISK)

Risk to Life
                                                                         developed areas, where works can be carried out as
Most of       us   have   some      difficulty grappling with the
                                                                         part of the development to limit risk. The tolerable level
concept of risk and deciding whether, or not, we are                     is raised      to   1:1 0,000 in        established     areas, where
prepared to accept it. However, without doing any sort
of analysis, or commissioning a report from an "expert",
                                                                         specific landslide hazards may have existed for many
                                                                         years.    The distinction is deliberate and intended to
we all take risks every       day. One of them is the risk of
                                                                         prevent the concept of landslide risk management, for
being killed in an accident. This is worth thinking about,               its own     sake, becoming             an    unreasonable financial
because it tells us a lot about ourselves and can help to
                                                                         burden    on    existing communities.Acceptable risk is
put an      assessed risk into        a   meaningful     context.   By
                                                                         usually taken to be one tenth of the tolerable risk
identifying activities that we either are, or are not,
                                                                         (1:1,000,000 for new developments and 1:100,000 for
prepared to engage in we can get some indication of                      established areas) and efforts should be made to attain
the maximum level of risk that we are prepared to take.
                                                                         these where it is practicable and financially realistic to
This knowledge can help us to decide whether we really
                                                                         do so.
are   able to accept      a   particular risk, or to tolerate a
particular likelihood of loss, or damage, to our property                                    TABLE 3: RISK TO LIFE
(Table 2).
                                                                           Risk (deaths per                Activity/Event Leading to
In Table 3, data from NSW for the years 1998 to 2002,                       participant per                              Death
and other sources, is presented. A risk of 1 in 100,000                          year)                        (NSWdata unless noted)
means that, in anyone year, 1             person is killed for every
100,000 people undertaking that particular activity. The
NSW        data    assumes        that    the    whole    population       1:1,000                     Deep sea fishing (UK)
undertakes the activity.           That is, we are all at risk of
                                                                           1:1,000            to
being killed in a fire, or of choking on our food, but it is                                           Motor cycling, horse riding         ,


reasonable to assume that only people who go deep                          1:10,000
                                                                                                       ultra-light flying (Canada)
sea   fishing run a risk of being killed while doing it.
                                                                                                       Motor vehicle use
It   can   be seen that the risks of dying            as a   result of     1:23,000
falling, using a motor vehicle, or engaging in water-
related activities (including bathing) are all greater than                1:30,000                    Fall
1:100,000 and yet few people actively avoid situations
where these risks are present. Some people are averse                      1:70,000                    Drowning
to flying and yet it represents a lower risk than choking
to death on food. Importantly, the data also indicate                      1:180,000                   Fire/burn
that, even when the risk of dying as a consequence of a
particular event is very small, it could still happen to any               1:660,000                   Choking on food
one of us any day. If this were not so, no one would

ever be struck by lightning.
                                                                           1:1,000,000                 Scheduled airlines (Canada)
Most       local   councils   and
                             planning authorities that
stipulate a tolerable risk to property also stipulate a                    1 :2,300,000                Train travel
tolerable risk to life. The AGS Practice Note Guideline
recommends that 1:100,000 is tolerable in newly.
                                                                           1 :32,000,000               Lightning strike


More information relevant to your particular situation may be found in other AUSTRALIAN GEOGUIDES:




                                                                             GeoGuide LR6          -

                                                                                                       Retaining Walls
            GeoGuide LR1      -
                                  Introduction
                                                                             GeoGuide LR8          -
                                                                                                       Hillside Construction
            GeoGuide LR2      -
                                  Landslides
                                                                             GeoGuide LR9          -
                                                                                                       Effluent & Surface Water Disposal
            GeoGuide LR3      -
                                  Landsldes in Soil
                                                                             GeoGuide LR10         -
                                                                                                       Coastal Landslides
            GeoGuide LR4      -
                                  Landslides in Rock
                                                                             GeoGuide LR11         -
                                                                                                       Record Keeping
            GeoGuide LR5      -
                                  Water & Drainage




The Australian GeoGuides (LR series) are a set of publications intended for property owners; local councils; planning authorities;
developers; insurers; lawyers and, in fact, anyone who lives with, or has an interest in, a natural or engineered slope, a cutting, or an
excavation. They are intended to help you understand why slopes and retaining structures can be a hazard and what can be done with
appropriate professional advice and local council approval (if required) to remove, reduce, or mini mise the risk they represent. The
GeoGuides have been prepared by the Australian Geomechanics Society. a specialist technical society within Engineers Australia, the
national peak body for all engineering disciplines in Australia, whose members are professional geotechnical engineers and engineering
geologists with a particular interest in ground engineering. The GeoGuides have been funded under the Australian governments’
National Disaster Mitigation Program.




                                   Australian Geomechanics Vol 42 No 1 March 2007                                        173