In addition to the devastating 1989 Newcastle earthquake, at least four other earthquakes of magnitude 5 or greater have occurred in the surrounding Hunter region since European settlement in 1804. Some of these earthquakes caused damage in areas that, at the time, were sparsely populated. Similar events, were they to occur today in populated areas, would certainly cause significant damage. The frequency with which these events have occurred in the Hunter region suggests that earthquakes pose a genuine threat to the communities there. This study presents the most comprehensive and advanced earthquake risk assessment undertaken for any Australian city to date. It has focused on the economic losses caused by damage to buildings from earthquake ground shaking, and not on the impacts from other, secondary hazards such as soil liquefaction and surface faulting. The study has adopted a probabilistic approach that makes allowances for the variability that is inherent in natural processes as well as the uncertainty in our knowledge. The results from this project will assist decision-makers involved in local and state government, policy development, the insurance industry, engineers, architects, and the building and finance industries to manage potential damage and loss of life from earthquakes in Newcastle and Lake Macquarie. The results also have implications for the earthquake risk facing larger Australian cities such as Sydney, Melbourne and Adelaide. This is due to a number of factors, including similarities between the earthquake hazard in Newcastle and Lake Macquarie and other parts of Australia, and similarities between the urban environments, particularly the composition of the building stock.

Poster describing the FIRE-DST project (GA contribution) focising on the developments in 2011/12 FY with respect to the Bushfire Risk Assessment Framework (BRAF) and the computational framework.

A study of the consistency of gust wind speed records from two types of recording instruments has been undertaken. The study examined Bureau of Meteorology's (BoM) wind speed records in order to establish the existence of bias between coincident records obtained by the old pressure-tube Dines anemometer and the records obtained by the new Synchrotac and Almos cup anemometers. This study was an important step towards assessing the quality and consistency of gust wind speed records that form the basis of the Australian Standards/NZ Standards for design of residential building (AS/NZS 1170.2:2002 and AS 4055:2006). The Building Code of Australia (BCA) regulates that buildings in Australia must meet the specifications described in the two standards. BoM has been recording peak gust wind speed observations in the Australian region for over 70 years. The Australia/New Zealand Wind Actions Standard as well as the wind engineering community in general rely on these peak gust wind speed observations to determine design loads on buildings and infrastructure. In the mid-1980s BoM commenced a program to replace the aging Dines anemometer with cup anemometer. During the anemometer replacement procedure, many localities had both anemometers recording extreme events. This allowed us to compare severe wind recordings of both instruments to assess the consistency of the recordings. The results show that the Dines anemometer provides higher severe gust wind speeds than the 3 cup anemometer when the same wind gust is considered. The bias varies with the wind speed and ranges from 5 to 17%. This paper presents the methodology and main outcomes from the assessment of coincident measurements of gust wind speed.

The Great Sumatra-Andaman Earthquake and Indian Ocean Tsunami of 2004 came as a surprise to most of the earth science community. Few were aware of the potential for the subduction zone off Sumatra to generate giant (Mw>= 8.5) earthquakes, or that such an earthquake might generate a large tsunami. In retrospect, important indicators that such an event might occur appear to have not been well appreciated: (1) the tectonic environment of Sumatra was typical of those in which giant earthquakes occur; (2) GPS campaigns, as well as paleogeodetic studies indicated extensive locking of the interplate contact; (3) giant earthquakes were known to have occurred historically. While it is now widely recognised that the risk of another giant earthquake is high off central Sumatra, just east of the 2004 earthquake, there seems to be relatively little concern about the subduction zone to the north, in the northern Bay of Bengal along the coast of Myanmar. It is shown here that similar indicators suggest the potential for giant earthquake activity is high: (1) the tectonic environment is similar to other subduction zones that experience giant megathrust earthquakes; (2) stress and crustal strain observations indicate the seismogenic zone is locked; and, (3) historical earthquake activity indicates that giant tsunamigenic earthquakes have occurred in the past. These are all consistent with active subduction in the Myanmar subduction zone, and it is hypothesized here that the seismogenic zone there extends beneath the Bengal Fan. The results suggest that giant earthquakes do occur off the coast of Myanmar, and that a very large and vulnerable population is thereby exposed to a significant earthquake and tsunami hazard.

INFORMING NATURAL HAZARD RISK MITIGATION THROUGH A RELIABLE DEFINITION OF EXPOSURE Krishna Nadimpalli, Mark Edwards, Mark Dunford Risk & Impact Analysis Group, Geoscience Australia GPO Box 378, Canberra, ACT 2601, Australia, krishna.nadimpalli@ga.gov.au Fundamental to any risk assessment is an understanding of the infrastructure and people exposed to the hazard under consideration. In Australia there is presently no nationally consistent exposure database that can provide this information. The need to better understand risk was recognised in the report on natural disaster relief and mitigation arrangements made to the Council of Australian Governments (COAG) in 2003. The report included a recommendation to develop and implement a five-year national program of systematic and rigorous disaster risk assessments. In response to this Geoscience Australia (GA) is undertaking a series of national risk assessments for a range of natural hazards. This work is being underpinned by a parallel development of a national definition of community exposure called the National Exposure Information System (NEXIS). The NEXIS aims to provide nationally consistent and best available exposure information at the building level. The building types considered are residential, business (commercial and industrial), and ancillary (educational, government, community, religious, etc.). NEXIS requires detailed spatial analysis and integration of available demographic, structural and statistical data. Fundamentally, this system is being developed from several national spatial datasets as a generic approach with several assumptions made to derive meaningful information. NEXIS is underpinning scenarios and risk assessments for various hazards. Included are earthquakes, cyclones, severe synoptic wind, tsunami, flood and technogenic critical infrastructure failure. The NEXIS architecture is completed and the system currently provides residential exposure information nationally. The prototype for business exposure is well developed and a national definition of business exposure will be generated by June 2008. Ancillary buildings and various critical infrastructure sector exposures will be incorporated into the future. While the present approach is largely generic, more specific building and socio-economic information will be incorporated as new datasets or sources of information become available. Opportunities also exist for NEXIS to be integrated with early warning and alert systems to provide real time assessments of damage or to forecast the impact for a range of hazards. This paper describes the methodologies used by NEXIS and how these will be advanced in the future to provide a more complete and specific definition of exposure to inform severe hazard risk assessment, risk mitigation and post event response.

FIRE NOTE 4 page article for the BCRC/AFAC information series.

Australian building codes through the Australia/New Zealand Wind Actions Standard as well as the wind engineering community in general rely to a significant extent on the peak wind gust speed observations collected over more than 60 years by the Bureau of Meteorology (BoM). The current wind loading code and the performance of our infrastructure (residential, commercial, industrial and critical infrastructure) is based primarily on the Dines anemometer interpretation of the peak gust wind speed. In the early 1990's BoM commenced a program to replace the aging pressure tube Dynes anemometer with the Synchrotac and Almos cup anemometers. As of October 2008 only six Dynes anemometers remain in operation.

The impacts of climate change, including sea level rise and the increased frequency of storm surge events, will adversely affect infrastructure in a significant number of Australian coastal communities. In order to quantify this risk, Geoscience Australia in collaboration with the Department of Climate Change and Energy Efficiency, have undertaken a first-pass national assessment which has identified the extent and value of infrastructure that are potentially vulnerable to impacts of climate change. We have utilised the best available national scale information to assess the vulnerability of Australia's coastal zone to the impacts of climate change. In addition to assessing coastal vulnerability assuming the current population, we also examined the changes in exposure under a range of future population scenarios provided by the Australian Bureau of Statistics. Continuation of the current trend for significant development in the coastal zone increases the number and value of residential buildings potentially vulnerable by 2100. We found that over 270,000 residential buildings are potentially vulnerable to the combined impacts of inundation and recession by 2100. This equates to a replacement value of approximately AUD$72 billion. Nearly 250,000 residential buildings were found to be potentially vulnerable to inundation only, which equates to AUD$64 billion. Queensland and New South Wales have the largest vulnerability (considering both value and number of buildings affected). Nationally, approximately 33,000 km of road and 1,500 km of rail infrastructure are potentially at risk by 2100. These results are influencing policy and adaptation planning decisions made by federal, state and local government.

CSIRO climate change projections based on the IPCC Fourth Assessment Report indicate that Tasmania is one of the areas within the Australian region that will experience an increased magnitude of severe winds. This study utilises the Climate Futures for Tasmania (CERF project) fine scale climate projections which provide spatial detail of the increasing wind hazard derived through dynamic-downscaling utilizing a regional climate model forcing by 5 GCM's and two climate change scenarios (detailed by Sanabria and Cechet; this conference). These wind hazard estimates are used to determine the impact of the wind hazard on residential infrastructure in the Tasmanian region. Two regions of Tasmania were assessed, one in the north and one in the south. The risk assessment involves an understanding of exposure and wind vulnerability. Built environment exposure information was provided by the National EXposure Information System (NEXIS) developed by Geoscience Australia. Wind vulnerability relationships (relating gust wind speed to damage) were developed by Geoscience Australia through a series of expert workshops and the analysis of wind damage data. Return periods of exceedence loss levels were evaluated at buildings level across each region. These were subsequently used to evaluate annualised losses, which represent the average annual cost to the region of exposure to the wind hazard if viewed through a very wide window in time. Expressing the annualised loss as a percentage of the total reconstruction value gives a measure of the intensity of the risk to the studied community that is not as evident from simple dollar values. Risk projections for the Tasmanian region will be presented and the relationship between wind hazard and risk explored. These outputs will be crucial to informing climate change adaptation options regarding severe winds which should be of significant concern to planning, construction, emergency services and the community as a whole.

Geographical information systems (GIS) have been used to model building flood damage in South East Queensland. The research shows that if a flood with a 1% annual exceedence probability (AEP) occurred simultaneously in all rivers in the region, 47 000 properties would be inundated, with about half of the properties likely to experience overfloor flooding. 90% of affected properties are located in the Brisbane-Bremer River system and the Gold Coast catchment. 89% of properties affected by flooding are residential. Nearly 60% of the residential flood damage is located in the Brisbane-Bremer River system, with damage estimated to be highest in those areas which historically have suffered high flood losses. Equivalent average damage per residential building is highest in the Gold Coast catchment. If the cost of the actual damages were to be spread among all residential buildings in South East Queensland, than the equivalent flood damage would be 1.09% damage from a flood with a 1% AEP.