Geotechnical Report

Risk to Life                                                                In NSW, the planning authorities consider that 1:1,000,000 is
                                                                            the maximum tolerable risk for domestic housing built near
Most of us have some difficulty grappling with the concept of               an obvious hazard, such as a chemical factory. Although not
risk and deciding whether, or not, we are prepared to accept                specifically considered in the NSW guidelines there is little
it. However, without doing any sort of analysis, or                         difference between the hazard presented by a neighbouring
commissioning a report from an "expert", we all take risks                  factory and a landslide: both have the capacity to destroy life
every day. One of them is the risk of being killed in an                    and property and both are always present.
accident. This is worth thinking about, because it tells us a lot
about ourselves and can help to put an assessed risk into a                 TABLE 3 – RISK TO LIFE
meaningful context. By identifying activities that we either                  Risk (deaths per     Activity/Event Leading to Death
are, or are not, prepared to engage in, we can get some                        participant per         (NSW data unless noted)
indication of the maximum level of risk that we are prepared                        year)
to take. This knowledge can help us to decide whether we
really are able to accept a particular risk, or to tolerate a
                                                                                1:1,000             Deep sea fishing (UK)
particular likelihood of loss, or damage, to our property
(Table 2).                                                                      1:1,000        to
                                                                                                    Motor cycling, horse riding, ultra-
                                                                                1:10,000
In Table 3, data from NSW for the years 1998 to 2002, and                                           light flying (Canada)
other sources, is presented. A risk of 1 in 100,000 means that,                                     Motor vehicle use
in any one year, 1 person is killed for every 100,000 people                    1:23,000
undertaking that particular activity. The NSW data assumes
that the whole population undertakes the activity. That is, we                  1:30,000            Fall
are all at risk of being killed in a fire, or of choking on our food,
but it is reasonable to assume that only people who go deep                     1:70,000            Drowning
sea fishing run a risk of being killed while doing it.
                                                                                1:180,000           Fire/burn
It can be seen that the risks of dying as a result of falling, using
a motor vehicle, or engaging in water-related activities                        1:660,000           Choking on food
(including bathing) are all greater than 1:100,000 and yet few
people actively avoid situations where these risks are present.                 1:1,000,000         Scheduled airlines (Canada)
Some people are averse to flying and yet it represents a lower
risk than choking to death on food. The data also indicate that,                1:2,300,000         Train travel
even when the risk of dying as a consequence of a particular
event is very small, it could still happen to any one of us today.              1:32,000,000        Lightning strike
If this were not so, there would be no risk at all and clearly
that is not the case.


More information relevant to your particular situation may be found in other Australian GeoGuides:

          GeoGuide LR1       - Introduction                                      GeoGuide LR7 - Landslide Risk
          GeoGuide LR3       - Soil Slopes                                       GeoGuide LR8 - Hillside Construction
          GeoGuide LR4       - Rock Slopes                                       GeoGuide LR9 - Effluent & Surface Water Disposal
          GeoGuide LR5       - Water & Drainage                                  GeoGuide LR10 - Coastal Landslides
          GeoGuide LR6       - Retaining Walls                                   GeoGuide LR11 - Record Keeping


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 minimise 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.




February 2019