Critical Infrastructure and the Earthquake Hazard
Background
The Building Management division of the Department of Planning,
Transport and Infrastructure (DPTI) is the Earthquake Hazard Leader for
South Australia. The State Emergency Management Plan identifies the
earthquake hazard as one of ten hazards which also includes bushfire,
flood, extreme weather and terrorism. Hazard Leaders are required to:

work with various advisory groups and functional services in order to
ensure that all aspects of the State’s approach to the hazard,
including mitigation, response and recovery measures are coordinated;

develop a State Level Hazard Plan; and

provide a review function across Prevention, Planning, Response
and Recovery.
Earthquake Hazard Description
Earthquakes can occur without warning at any time of the year. They
occur over very short time frames, usually less than one minute. A series
of smaller earthquakes known as aftershocks will often occur following the
main earthquake.
Earthquakes can cause great physical and societal impact over a broad
geographic region. Entire cities can be affected to some degree by a
moderate earthquake.
The principal hazard of an earthquake is ground shaking. Ground shaking
accounts for approximately 90% of earthquake damage. Secondary
hazards include:

fire;

damage to containers holding hazardous materials;

landslides and rock falls;

fault ruptures; and

tsunami.
South Australia’s Earthquake Risk
By world standards, Adelaide’s earthquake risk is low to moderate,
however by Australian standards Adelaide has the highest risk of all
capital cities. Seismologists advise earthquakes up to Richter Magnitude
7.5 can occur in South Australia.
The largest known earthquake to occur in South Australia was M6.5 at
Beachport in 1897. The best known earthquake was the M5.5 Adelaide
earthquake of 1954. The 16 April 2010 M3.8 earthquake near Mount
116093152
Updated April 2012
Critical Infrastructure and the Earthquake Hazard
Barker reminds us that earthquake needs to be a consideration for critical
infrastructure owners and managers in the State.
Critical Infrastructure Vulnerability to Earthquake
The following aspects of critical infrastructure should be considered in
regard to earthquake.
Buildings of the following types are most vulnerable:

unreinforced masonry buildings;

buildings with tall chimneys and unrestrained parapets;

buildings with open shop fronts and soft storeys (storeys with much
lower resistance to seismic loads than other storeys in the building);
and

buildings with existing structural damage/cracking.
Electric power systems are vulnerable in the following areas:

substation equipment – unanchored transformers, battery racks,
and busbars;

porcelain insulators – the size and fragility of porcelain insulators
increases with voltage and so does the risk of damage to them in an
earthquake; and

control houses – damage to control equipment and emergency
control centres.
Water systems and sewers are vulnerable in areas where there are:

old and corroded pipelines – cast iron pipes and asbestos pipes
typically have higher failure rates than ductile iron, steel or PVC
pipes;

pipelines in soft soils, ground susceptible to liquefaction or
landslides; and

systems relying upon electricity supply – water and sewer pump
stations, water filtration and sewer treatment plants cannot operate
without power.
Communication systems are vulnerable due to:

system overload – huge increases in call volumes can be expected
to all emergency telephone numbers;

loss of electricity supply; and

damage to data centres, exchange buildings and the equipment
within.
Gas supply systems are vulnerable where there are:

old and corroded pipelines – cast iron pipes typically have higher
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Critical Infrastructure and the Earthquake Hazard
failure rates than ductile iron, steel or PVC;

pipelines in soft soils and ground susceptible to liquefaction;

rigid connections to appliances which topple or slide causing gas
lines to rupture; and

mass service shutoffs requiring relighting.
Business Continuity Planning
There are a number of actions you can take now and into the future to
reduce your exposure to the Earthquake Hazard.
System Redundancy – Design to ensure failure of parts of a system
does not lead to total system failure.
Memorandums of Understanding – Make prior arrangements for
external assistance to boost response and recovery capacity following an
emergency.
Planning and Logistics – Have critical spare parts and equipment
available and stored safely and securely in storage racks adequately fixed
and braced. Store heavy items near floor level.
Technical – Make prior arrangements for technical advice and inspection
of services and structures following an emergency.
Financial Arrangements – Plan for large capital expenditures following
an emergency.
Emergency Communications – Ensure communications can be
maintained within the business during an emergency.
Staffing Arrangements – Assign emergency management and
responder roles with backup and change of shift staffing in place.
New Work to Code – Brief designers on the importance of new work
complying with earthquake codes and detailing requirements.
Seismic Upgrading – Undertake seismic analysis and upgrade of
vulnerable and/or critical elements of systems.
Information to Customers – Provide information on the use of services
and turning off/restoring service following an emergency.
Information
For further information please refer to:
Websites
Department for Manufacturing, Innovation, Trade, Resources and Energy
(DMITRE)
www.pir.sa.gov.au/minerals/earthquakes
Geoscience Australia
www.ga.gov.au
State Emergency Service
www.ses.sa.gov.au
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Critical Infrastructure and the Earthquake Hazard
Alternatively you can contact:
Sergeant John Hood
Critical Infrastructure Support Group
South Australia Police
Phone:
Email:
08 7322 3625
john.hood@sa.gov.au
Shane Turner
Principal Engineer, Structural
Building Management, DPTI
Phone:
Email:
08 8226 5223
shane.turner@sa.gov.au
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