Earthquake

Chapter Nine:



Earthquake









Ea thqu ke | C apt

Damage sustained by the Workers Club following an earthquake in Newcastle, New Southr Wales,aDecemberh1989e r x x x | p a g e 1 3 3

Photo courtesy: Emergency Management Australia.

Earthquake

Earthquakes pose a risk that is fundamentally different



to those of more frequently occurring natural hazards



such as tropical cyclones and floods. Australia is a



tectonically stable region and has few earthquakes of



any consequence in any given year. The relative rarity



of large earthquakes ensures that earthquakes are not



prominent in the public consciousness. However, the



earthquakes in Newcastle, New South Wales, in 1989,



in Meckering, Western Australia, in 1968, and in



Adelaide in 1954 clearly demonstrated that moderate-



sized earthquakes have the potential to tragically affect



Australian communities.









Damage to a building from an earthquake in Meckering,

Western Australia, October 1968

Photo courtesy: Emergency Management Australia.

A fault scarp caused by a prehistoric earthquake at Lake Edgar,

Tasmania, circa 15,000 BC

Photo courtesy: Geoscience Australia.

A car damaged by falling rubble from an earthquake in

Newcastle, New South Wales, December 1989

Photo courtesy: Emergency Management Australia.

A warped pipeline from an earthquake near Tennant Creek,

Northern Territory, January 1988

Photo courtesy: Emergency Management Australia.









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While the severity of earthquakes in Australia is rocks fracture generates seismic waves, and

not as great as at tectonic plate boundaries, the these cause ground shaking when they reach

typically higher vulnerability of infrastructure the surface of the earth.

can lead to severe consequences. The Newcastle

Most earthquakes occur along plate edges (i.e.

experience showed how vulnerable Australian

‘inter-plate’), where the plates meet and are forced

cities are to earthquakes, resulting in death,

against each other. Some 95% of earthquakes are

injury and substantial economic loss. The average inter-plate, with 80% of all recorded earthquakes

annual cost of earthquakes in Australia is $144.5 occurring around the edge of the Pacific plate,

million taken over the period from 1967 to 1999 which includes Canada, Japan, New Zealand,

(BTE 2001); most of this can be attributed to Papua New Guinea, South America and the

one key event, the Newcastle earthquake which United States.

resulted in 13 fatalities. The historical records of

Australia is situated within the Indian-

earthquakes demonstrate that large earthquakes

Australian plate and is not on the edge of a

do occur in Australia and there is no doubt that

plate, so its earthquakes are ‘intra-plate’ and are

a large earthquake has the potential to cause

fundamentally different to the more common

massive destruction and loss of life in Australian

inter-plate earthquakes. The Indian-Australian

communities.

plate is being pushed north and squeezed between

There are still significant gaps in the the Antarctic, Eurasian, Philippine and Pacific

understanding of earthquakes in Australia. Both plates. The stress from this squeezing builds up

government and non-government agencies have as compression within the Australian continent

a role to play in filling these gaps, through the and is released during an earthquake.

acquisition of fundamental data and through Earthquake sizes are often compared using the

research into hazard and risk. Improving our Richter magnitude scale. This scale is based on

understanding of earthquake hazard and the risk the maximum amplitudes of the seismic waves

posed to communities and infrastructure will lead generated by the earthquake. The magnitude of

to better strategies for mitigation and emergency an earthquake is an estimate of the energy released

response. This chapter describes the process of by it. For every unit increase in magnitude on

earthquake risk analysis, and points to some of the Richter scale, there is roughly a thirty-fold

the issues that still need to be addressed. increase in the energy released by an earthquake.

For instance, a magnitude 2 earthquake releases

Hazard Identification 30 times more energy than a magnitude 1

The earth’s outer shell is about 100–200 earthquake. The difference in the energy released

kilometres thick and is broken into nine major between earthquakes of magnitudes 3 and 1 is

and several smaller plates. These plates are 900 times (30 x 30).

constantly moving away from, towards or past In populated areas, the effects seen during

each other; because the continents are part an earthquake depend on many factors,

of these plates, they also move. Earthquakes such as the distance of the observer from the

occur when the stresses caused by the plate epicentre. Even small earthquakes will be felt

movements result in the rocks fracturing along if very close, but generally the effects will be as

fault planes. The energy released when the shown in Table 9.1.









Earthquake | Chapter Nine | page 135

In Australia the principal hazard component of One diarist, Blackburn, wrote (Cobley 1987, p. 167):

earthquakes is the associated ground shaking. This ‘The shock did not last more than two seconds.

shaking can damage or destroy structures, which It came from the (southwest) like the wave of

in turn can cause injuries or deaths. However, the sea, accompanied by a noise like a distant

there are numerous other hazards associated cannon. The trees shook their tops as if a gale

with earthquakes, such as liquefaction and fault of wind was blowing.’

ruptures. Liquefaction occurs when shaking Another noted that (Bradley 1802, p. 115):

causes water to be expelled from the subsurface

‘This shock was distinctly felt on board the ships

sediments and soil, leading to ground failure and in the cove and by several people on shore, who

loss or weakening of building foundations. Fault supposed it to be the shock of an earthquake.’

ruptures occur when the earthquake is shallow

Adelaide has the highest earthquake hazard of

and the fault reaches the surface and displaces it

any Australian capital city (AS 1170.4-1993),

horizontally and vertically.

having had more medium-sized earthquakes in

Although earthquakes are nowhere near as the past 50 years than any other. South Australia

common in Australia as on plate boundaries, is slowly being compressed at an estimated rate

of 0.1 millimetres each year (Leonard in review);

Australia has a long history of earthquakes.

the stress builds up in the rocks over many

The first recorded event occurred near Sydney

years, until they break and cause an earthquake.

Cove on 22 June 1788, just five months after

Earthquakes cannot be predicted, but measuring

European settlement began. Many of the first these changes, in the context of Adelaide’s

settlers mentioned the event in their diaries. earthquake history, helps researchers to estimate

Their descriptions help us understand the source the likelihood of earthquakes in the region

and magnitude of the earthquake. around Adelaide.



MAGNITUDE EFFECTS



8.0 Causes total damage, waves are seen on the ground surface and objects are thrown in the air





Table 9.1: Earthquake magnitudes and typical associated effects

Note: Events between magnitudes of roughly 2.0 and 3.4 may be felt within a few kilometres of the epicentre.









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Australia’s largest recorded earthquake occurred the losses in the decade from 1980 to 1989 are

in 1941 at Meeberrie, Western Australia. Its almost entirely from a single, catastrophic event,

magnitude is estimated to be 7.2 but, fortunately, the earthquake in Newcastle in 1989 which

it occurred in a remote area. The magnitude resulted in 13 deaths and injured 130, and had

6.8 earthquake that occurred at Meckering in an overall cost of around $4.5 billion.

1968 caused extensive damage to buildings and

was felt over most of the southern part of the Risk Analysis

state. Earthquakes of magnitude 4 or more are The general approach to estimating earthquake

fairly common in Western Australia, with one risk is to model numerous earthquakes and to

occurring approximately every five years in the estimate the consequences associated with each

Meckering region. For four years, Burakin, 150 event as well as the probability of such an event

kilometres east of Perth, has been Australia’s occurring. This process requires five key models:

most active earthquake region. A magnitude 5.0

earthquake in September 2001 was followed by an earthquake source model that describes

18,000 much smaller earthquakes over the next the likelihood of an earthquake of a given

six months. magnitude occurring in a given location

a ground motion model that defines the ground

Cost of Earthquakes shaking experienced at a given distance from a

simulated earthquake of a specific magnitude

Earthquakes pose a particularly challenging

risk to Australian communities in that they a site response model which estimates the level

are relatively rare events but have the potential of local ground amplification

to cause catastrophic losses. This can be seen an exposure model that describes the number

from an analysis of historic earthquake losses in of structures exposed to earthquake-induced

Australia (as shown in Figure 9.1). The average ground shaking

annual cost of earthquakes in Australia is $144.5 a vulnerability model that characterises the

million (BTE 2001); over the period from 1967 to nature, magnitude and economic cost of the

1999, there is only one decade with losses due to damage that structures will experience when

earthquakes in excess of $250 million. However, exposed to ground shaking.

5000







4000

$A(1998) million









3000







2000







1000

06-1365-8









0

1960-69 1970-79 1980-89 1990-99

Decade of event



Figure 9.1: Total cost of earthquakes in Australia by decade, 1967 to 1999

Source: BTE (2001), Figure 3.24.





Earthquake | Chapter Nine | page 137

Police rescue squad looking in the rubble for survivors following an earthquake in Newcastle, New South Wales, December 1989

Photo courtesy: Emergency Management Australia.







Likelihood Analysis energy and earthquakes are felt over unusually

A likelihood analysis for earthquakes is aimed long distances. These models are very region

at determining the chance of an earthquake dependent, and to date very little is known about

occurring at a specific location. Because of the what the appropriate ground motion model for

relative rarity of earthquakes in Australia, it is Australian conditions should be.

not yet possible to identify the specific faults Local soils and shallow geological sediments

on which earthquakes will occur in future. (collectively known as ‘regolith’) affect the

Therefore, an earthquake likelihood analysis is ground motion, and models must be modified

generally conducted through the use of source to account for these effects. The shaking by a

models which divide Australia into regions seismic wave that moves from hard rock into

that are considered to have a consistent rate of regolith is amplified because of several factors

earthquake occurrence. The aim is to identify which significantly increase the risk of damage

broad regions that are more or less likely to from an earthquake. These include the increased

have earthquakes. These regions are typically amplitude required to transmit a given amount

derived from an interpretation of the historical of energy and the resonance effects within surface

earthquake records within Australia, combined layers. It is possible to develop detailed models

with an understanding of regional geology. that account for the effect of regolith; however,

this requires detailed geological and geotechnical

An earthquake likelihood analysis can be data, such as shear-wave velocity and regolith

extended to produce an earthquake hazard map thickness, which are generally available only for

that can be used to underpin building codes. An urban centres.

earthquake hazard map for Australia is shown in

Figure 9.2. The development of an earthquake Data requirements

hazard map requires not only an understanding Determining the likelihood of earthquakes

of the occurrence of earthquakes, but also a relies on the availability of a consistent, high-

ground motion model that describes how the quality record of the magnitude and location

intensity of ground shaking decays as distance of earthquakes in Australia. Until the late

from an earthquake increases. For example, in 1970s, Richter’s formula was generally used to

the regions of Australia which are geologically calculate the local magnitude at all Australian

old such as Western Australia, the rocks are observatories. In the late 1980s and early 1990s

hard, so there is relatively little absorption of most observatories developed their own local









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magnitude scales, with several observatories ground shaking from earthquakes. Ideally,

changing their approach more than once. recordings from large earthquakes are used

directly to produce models to predict the ground

The use of different magnitude scales has resulted shaking from future earthquakes. However, due

in magnitudes for same-sized earthquakes to the rarity of large earthquakes in Australia,

recorded prior to 1990 and since 1990 differing there are virtually no high-quality recordings

up to 0.5 magnitude units, though this is also of ground motion for large earthquakes at

partly the result of seismograph instrumentation distances closer than hundreds of kilometres.

changing from traditional pen recorders to An alternate approach is to use the ground

digital recorders. This is equivalent to a factor of shaking recorded from small earthquakes to help

10 in energy release. Producing a comprehensive predict the shaking that would be associated

earthquake catalogue with consistent magnitude, with large earthquakes, but this is complicated

both between regions and in time, is a key by differences in the vibration frequencies from

requirement, and requires high-quality seismic small and large earthquakes.

data to develop regional earth models.

The final dataset required to understand the

The development of ground motion models hazard associated with earthquakes is detailed

depends upon high-quality recordings of the information on the regolith. In particular, it







Darwin





Birdum

Cairns



Townsville







Alice Springs

Rockhampton









Brisbane









Perth

0 500 km Newcastle

Adelaide Canberra Sydney



Acceleration coefficient (a) 10% chance Melbourne

of being exceeded in 50 years



0.10





Acceleration coefficient contours

Hobart 07-2256-6





Figure 9.2: Earthquake hazard map of Australia

Source: Geoscience Australia.









Earthquake | Chapter Nine | page 139

is necessary to have data on the thickness and a disruption to business activity, through the loss

shear-wave velocity of the regolith in order to of stock and damage to the means of production.

accurately understand its effect on earthquake The direct damage to structures is typically

hazard. These data can be collected by a variety estimated through the use of engineering models

of methods, ranging from geotechnical studies, that relate the likely degree of structural damage

including seismic cone penetrometer tests, to the severity of ground shaking (Robinson and

through to passive monitoring techniques that others 2005).

use seismic noise (generated by cars, pedestrians,

ocean waves etc.) to determine the regolith’s For discrete residential buildings, these

properties. However, it is critical to recognise that vulnerability models are typically associated

regolith can be very spatially variable. Therefore, with the wall and roof type. Residential house

the required data need to be captured at a high walls usually brace the building for lateral loads.

spatial resolution in order to accurately model Some wall types, such as unreinforced double

the hazard. brick, have been associated with greater losses

from earthquake damage than other types,

Consequence Analysis such as framed wall systems (Edwards and

Consequence analysis is focused on examining others 2004). Analysis of insurance claim data

the elements that are subjected to a specific derived from the Newcastle earthquake in 1989

hazard, and their associated vulnerability. revealed that the repair costs for unreinforced

masonry buildings were double those for

It is important to recognise that it is inappropriate timber-framed constructions exposed to the

to determine the consequences of earthquakes, same intensity of ground shaking. Heavier,

unlike hazards such as riverine flood, from a tiled roof construction also influences damage

hazard map. The extent of a flood is largely outcomes by accentuating inertia loads, while

constrained by the geometry of the river channel much lighter sheet metal–clad roofing reduces

and floodplain being considered. Therefore, a the demands on the bracing walls.

flood hazard map is generally representative of a

single flood event, and it is realistic to determine For commercial and industrial buildings the

the consequences of such an event from a vulnerability model is generally related to the

hazard map. In contrast, earthquakes can occur structural system and the nature of infill walls.

anywhere, meaning an earthquake hazard map is Australian reinforced concrete frame systems,

not representative of any single earthquake. An while massive, inherently possess a degree of

earthquake risk map is normally produced by ductility that has been shown to be generally

modelling the damage caused by a large number adequate for the Australian seismic hazard.

(e.g. thousands) of synthetic earthquakes, and However, in some instances stiff infill walls have

weighting them according to their magnitude not been separated from the structural elements,

and source zone. leading to a compromised resistance.



Earthquakes are like many other hazards in that Building vulnerability research is by no

they have great potential to disrupt communities. means mature in Australia, and an improved

Seismic events do this directly through damage understanding of susceptibility of buildings

to buildings and, less directly, through the to earthquake hazard is challenged by a lack of

damage they cause to the infrastructure that well-documented historical data. Consequently,

communities rely upon. Damage to building damage model research is now more focused on

contents causes further impact on residents and developing an understanding of the engineering









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system than on using actual loss data to produce tool (National Institute of Building Sciences

empirical models. Furthermore, engineering 2003) was used to model the damage caused by

models validated against the available data can representative earthquakes. Similar models that

be used to identify mitigation options for more separately examine the individual components

vulnerable structures, and to quantify their of more complex assets are under development

effectiveness. and are aimed at predicting the damage to

other critical infrastructure assets, such as large

One of the main indirect effects from earthquakes storage tanks, thermal power stations, electrical

is their potential to disrupt essential utility substations and telephone exchanges. This

services, such as electricity, water and gas supply, work will lead to a more complete picture of

along with transportation systems. This has the vulnerability of Australian communities to

been illustrated in recent damaging Australian earthquake hazard.

earthquakes. An earthquake in Tennant Creek,

Northern Territory, in 1988 severely damaged Data requirements

the main gas pipeline from Tennant Creek to A consequence analysis has the same data

Darwin, although there was no disruption to requirements as the likelihood analysis described

supply in that case. The Newcastle earthquake above. In particular, it is essential that realistic

caused significant damage to high-voltage circuit models of earthquake likelihood and associated

breakers at the Kilmore electrical substation, ground shaking are used in order to accurately

thereby disrupting supply. There are considerable model the consequences of earthquakes. If a

lead times for the replacement of some vulnerable site-specific study is going to be conducted (e.g.

asset types, such as high-voltage transformers. for critical facilities or infrastructure), it is also

important to have accurate, detailed geotechnical

The widespread impact of damage to critical

information at the site of interest.

infrastructure assets has highlighted the need

to better understand their vulnerability. The In addition to the information on the earthquake

disruption of major highway corridors was the hazard, current earthquake damage models for

subject of work by Dale and others (2005) in buildings typically require information such as

which an approach from the HAZUS-MH each structure’s construction type (i.e. wall and









A collapsed house following an earthquake in Meckering, Western Australia, October 1968

Photo courtesy: Emergency Management Australia.





Earthquake | Chapter Nine | page 141

Damage sustained to the Workers Club following an earthquake in Newcastle, New South Wales, December 1989

Photo courtesy: Emergency Management Australia.







roof material), number of storeys, floor area and The zonation for the Brown and Gibson (2004)

replacement value. Structural information is also model is based on regional geology. Although

required for critical infrastructure in order to geological deformation and faulting was

model the impact of earthquakes. considered in quantification of the zones, the

activity estimates rely heavily on the short period

Information Gaps of historical earthquake activity. However, this

A fundamental problem in Australia is the limited fundamental assumption has not been rigorously

availability of the basic physics and engineering tested. Furthermore, there is some indication that

seismicity in a given region, and on individual

models that underpin any earthquake risk

faults, is highly episodic (Crone and others 1997;

analysis. The development of these models has

Crone and others 2003; Leonard in review).

been particularly difficult in Australia because of

the rarity of large earthquakes and the associated The rarity of earthquakes in Australia means

lack of data. The following section describes the it would take thousands of years to record

gaps in earthquake source and ground motion enough events to confidently understand the

models and vulnerability research, as well as the distribution of future earthquakes. However,

research required to address these gaps. a careful study of the Australian landscape can

provide evidence of prehistoric earthquakes

Earthquake Source Models that can be used to improve earthquake source

Earthquake source models are generally produced models. This neotectonic evidence can be used

from an interpretation of the historical record of to extend our understanding of the history of

earthquakes in Australia. However, there is no earthquakes in Australia back tens of thousands

clear consensus as to how the limited historical of years (Clark 2006).

record should be interpreted. There are at least In addition to identifying prehistoric

three published source models available (Leonard earthquakes in the landscape, it is possible to

in review; Gaull and others 1990; Brown and use precise measurements of the deformation

Gibson 2004). The underlying assumption in the Australian crust, combined with

for most of these models is that the history of numerical modelling, to try to identify

earthquakes in the past century is an accurate regions that are more likely to experience

indicator of the likely occurrence of earthquakes earthquakes in the future. This work requires

in the future. repeated observations of landmarks to detect









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sub-millimetre movements over the course of As mentioned previously, there is also a need

many years. Given time, this work will provide to develop models that describe the effect of

a more realistic understanding of the regolith on earthquake ground shaking. The

deformation of the Australian crust that can be development of these models is fundamentally

used to improve our earthquake source models. limited by the availability of detailed geotechnical

data. These data are particularly crucial in urban

Ground Motion Models areas where consequence analyses are usually

The first ground motion model developed for conducted. In many urban areas significant

Australia using only Australian data was the amounts of data are held by local councils,

Gaull and others (1990) model. This model industry and the state government, but no urban

is based entirely on seismic intensity data, area has a single comprehensive database of this

which are obtained from personal perceptions information. Another potential source of such

of shaking and damage. Because engineering data is the datasets acquired for the development

damage models typically need more information of infrastructure such as bridges and tunnels.

than seismic intensity, earthquake hazard and risk These projects often require geotechnical studies

assessments in Australia generally adopt ground as part of the construction process.

motion models from other stable continental

Vulnerability Research

regions, such as eastern North America (e.g. Dhu

Building vulnerability research in Australia

and Jones 2002).

is challenged by a lack of well-documented

However, there has been very little analysis historical data. Sufficient structural damage and

undertaken to show whether these models are loss data do not exist to permit the development

applicable to Australian conditions. For example, of empirical models. There are further difficulties

an analysis of data recorded during the earthquake in assessing the local hazard that caused damage,

sequence at Burakin, Western Australia, in 2001 due to a lack of strong motion records. This is

and 2002 (Allen and others 2006) suggests that, unlikely to change in the near future. Therefore,

at small distances from the earthquake, higher damage model research is now more focused on

ground motions are observed compared with developing an understanding of the engineering

eastern North America. This results in ground system.

shaking in southwest Western Australia that The use of engineering models can provide the

decreases at a lower rate with distance compared opportunity to identify and assess the effectiveness

to ground shaking in eastern North America for of mitigation options where vulnerabilities exist.

an earthquake of the same magnitude. However, Additional research needs to be done to better

this may also be due to the influence of surface predict physical damage and to include economic

waves from these shallow events. cost. Furthermore, the detailed analysis in some of

this work needs to be generalised so that reliable

As the quality of seismic data recorded in

assessments of damage and cost can be made for

Australia continues to improve, there is a

large populations of building structures.

continuing need to use these data to develop

Australia-specific ground motion models. The vulnerability of critical infrastructure to

The current lack of data will result in large earthquake is less well understood than that

uncertainties in these models; however, this will of building structures. Critical infrastructure

improve over time as modelling techniques are can comprise extremely complicated systems

refined and the amount of data increases. with many components that are all vital to









Earthquake | Chapter Nine | page 143

successful operation (e.g. the complex systems required for risk analysis can only be acquired in

comprising a coal-fired thermal power station). collaboration with state and territory agencies.

The components within a system each have

their own seismic vulnerability, and knowing Local Government

each of these is essential to an understanding Local government agencies are involved in

of the overall vulnerability and prognosis for planning and mitigation, as well as emergency

restoration of the asset. response at the local level. An accurate

understanding of earthquake risk requires some

Roles and Responsibilities components that are very site specific, such as

Management of earthquake risk cuts across all an understanding of the local regolith and a

levels of government, non-government agencies comprehensive building inventory.

and groups, and the general community. The

analysis of earthquake hazard and risk requires Industry, Coordinating Groups,

collaboration between these sectors as each has Professional Bodies and Research

their own responsibility and role. Institutions

Australian Government A few professional bodies, coordinating groups

and industry bodies have an advocacy and/or

The Australian Government’s overarching goal in

coordinating role in earthquake risk mitigation.

the management of earthquake risk is to ensure

For example, the Australian Earthquake

the sustainability and prosperity of Australia’s

Engineering Society, a technical society of

communities. It provides financial assistance

Engineers Australia, promotes the practices

to help achieve this through its funding

of engineering seismology and earthquake

programmes aimed at reducing the risk of

engineering. Similarly, the Australian National

natural disasters. The Australian Government

Committee on Large Dams Incorporated has

also operates a national seismograph network

which monitors earthquakes in the region and supported research into earthquake hazard

maintains the Australian Earthquake Database. and arranged for earthquake data collected by

It also provides earthquake information and its members to be made available for research

undertakes research into reducing risk through purposes.

improved understanding of the earthquake The University of Queensland undertakes some

hazard and risk in Australia. However, numerous

research into earthquake hazard assessment as part

other collaborators also have crucial roles in

of a wider programme of investigating the physics

this process.

of earthquakes through the use of computer

State and Territory Governments simulations. The Australian National University

has a major seismic research programme in

State and territory governments play an

observational and theoretical seismology, with a

important role in earthquake risk management

focus on understanding the earth’s structure and

in Australia. Historically, the state and territory

processes, but undertakes minimal research into

governments have been involved in the

earthquake hazard.

preparation of emergency management plans

for earthquakes, the mitigation of earthquake Several universities in Australia (University

risk, and responses to earthquakes that have of Adelaide, Curtin University, University of

affected Australian communities. In addition Melbourne and University of Western Australia)

to these roles, some of the fundamental data undertake neotectonic geological investigations,









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and several universities in Australia (University An understanding of earthquake risk in Australia

of Adelaide, University of Melbourne, Monash requires an understanding of the fundamental

University, University of Newcastle and characteristics of earthquakes in Australia, how

Swinburne University of Technology) undertake their associated ground shaking propagates, the

research into the structural vulnerability of effects of local site conditions, the vulnerability

buildings to earthquakes. No university in of buildings, and the exposure of buildings and

Australia has a major programme of earthquake people to the ground shaking.

hazard research.

To develop new and improved models in these

The Seismology Research Centre within areas requires high-quality earthquake and

Environmental Systems and Services, Melbourne,

ground motion data, along with comprehensive

monitors seismic activity in eastern Australia

building and infrastructure performance data

with its own networks, and undertakes hazard

and inventories. By combining these models it is

studies both within Australia and overseas.

possible to understand the risk, and to minimise



Conclusion the chance of catastrophic losses by improving

the design of structures through appropriate

The earthquake hazard risk is low in Australia

building codes.

compared to more seismically active regions of

the world, but there is potential for a disastrous Gaps in the knowledge and information that is

and costly event. Historically the average annual required to achieve these outcomes, particularly

economic loss caused by earthquakes has been in the areas of earthquake source models, ground

low at $144.5 million per year or about 13% of motion models and vulnerability research,

the cost of natural disasters; however, events such need to be addressed, and the three levels of

as the Newcastle earthquake which resulted in

government, as well as industry and academia,

13 deaths and a total loss of about $4.5 billion,

all have important roles to play.

demonstrate the potential for very significant

overall cost to the community.









A fault scarp caused by an earthquake in Meckering, Western Australia, October 1968

Photo courtesy: Geoscience Australia.





Earthquake | Chapter Nine | page 145

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