The Risk and Impact Analysis Group (RIAG) at Geoscience Australia (GA) in Canberra is a multidisciplinary research team. Their key role is to develop knowledge on the risk from natural and human-caused hazards for input to policy and operational decision makers for the mitigation of risk to Australian communities. The RIAG achieves this through the development of computational methods, models and decision support tools that assess the hazard, vulnerability and risk posed by hazards. The RIAG also works with other agencies to develop and collect information on natural disasters that is essential for developing valid risk models for forecasting the impact of future hazard events. The Group includes hazard experts, numerical modellers, engineers, economists, and GIS specialists. This paper will discuss the risk analysis process used at GA, with a particular focus on the vulnerability component. Earthquake and tsunami risk examples will highlight technical aspects of the work and step through the risk analysis framework that has been adopted. The method being used to develop vulnerability models for the wind and tsunami hazard is an engineering model approach. The method requires a generalised hazard definition, an engineering model of a particular structure, and a costing module to calculate the real cost of repairs. The initial focus will be Australian residential structures. The engineering model is based on the assumption that connection failure is the primary initiator of structural failure in residential structures (as opposed to say, a beam or wall stud failing in bending). It also assumes that component failures can be aggregated up into overall damage scenarios. The engineering model employs a Monte Carlo simulation approach that allows for the incorporation of variability (in connection strengths, building orientation, opening sizes, and key hazard parameters). The engineering model approach also allows the opportunity to investigate mitigation options through strengthening structural components. The multi-hazard risk approach used at GA is a move towards being able to make informed decisions on how to manage the risk from natural hazards. This paper has presented examples of computational natural hazard risk with a particular focus on the development of engineering vulnerability models. Presented at the International Forum on Engineering Decision Making, 12th to 15th Dec, 2007, Port Stephens, NSW.

Older unreinforced masonry (URM) buildings have been found to perform poorly in historical Australian earthquakes. Where these building are present in pedestrian precincts, they represent a significant risk to people and communities. Some towns and cities have a significant proportion of this type of building within business districts and Perth CBD is an example having 48% by number of URM construction ranging from pre-Federation to early-to-mid twentieth century in age. Further, these buildings are often of significant heritage value providing a sense of place to residents and contribute to visitor related business revenue. These factors all come to play in the town of York which is also in an area of elevated earthquake hazard. There is a need for information inform strategies and decision making around reducing the risk they represent. This project has had a focus on York and was designed as a three-year collaboration between researchers, industry and local stakeholders to improve the understanding of the vulnerability of older unreinforced masonry (URM) buildings. The building types considered are of the types found in York and other larger communities and the project has included methods of retrofit that can enhance the resilience of these buildings to earthquake hazard. It has further included the promotion of expertise with building design professionals and in the construction industry to undertake this work through a demonstration projects. Specifically, the project has been a collaboration between the Shire of York, the Department of Fire and Emergency Services, the University of Adelaide and Geoscience Australia. While not a direct project partner, the Department of Planning Lands and Heritage (DPLH) has also been a key stakeholder that has sought to facilitate the application for grant funding for the mitigation activity to be studied as part of this project.

Natural disasters provide an invaluable opportunity to capture data for improving our understanding of risk. Observed damage types and their predominance provide useful insights into the factors contributing to building vulnerability and consequential community risk. They also facilitate the appraisal of mitigation measures directed at reducing that risk where it is found to be high. Survey activities that followed the impact of Tropical Cyclone Larry have highlighted the benefits of a co-ordinated survey response to natural hazard impacts. The response to this event involved liaison with local emergency management and the broad participation of recognised wind engineering experts. Survey techniques were refined to achieve a more efficient and comprehensive approach that ensured consistency, utility and transferability of the data for all collaborators. The refined approach proved very successful and may provide a useful model for similar post-disaster exercises directed at earthquake damage. The sudden nature by which earthquakes inflict damage without warning points to having arrangements already established beforehand for the best survey outcomes. Proposals for advancing such preplanning are presented.

<div>The region of coastal South East Queensland (SEQ) is a large concentration of population, industry, and infrastructure important to the economy of Queensland and of Australia. The region is also subject to severe storms that generate damaging winds, particularly as result of thunderstorm and tropical cyclone activity. Older residential housing has historically been the most damaged in such storms, contributing disproportionately to community risk. This risk posed by severe wind is not well understood, nor are the optimal strategies for managing, and potentially reducing, this risk. In this hazard context, this project was initiated based on a joint proposal developed by Queensland Fire and Emergency Services (QFES), Geoscience Australia and the six coastal local governments in SEQ in January 2020. The objective was to gain an improved understanding of the wind risks in this region and to develop actionable information that could inform future strategies to manage and reduce risk in these areas, with broader application to other local government areas. The project proved to be of great interest to a broader range of stakeholders, including the insurance industry, some of whom became formal partners, while others participated as observers. </div><div><br></div><div>The management of wind risk requires a sound evidence base for decision makers. While the information developed in this project has significant uncertainties, the outcomes are considered a representative view of wind risk in a coastal region that is home to nearly 60% of the Queensland population. The work has developed an improved understanding of the three primary risk elements of wind hazard, residential exposure and vulnerability. This has been achieved through a broad collaboration that has entailed the sharing of data, domain expertise and consensus building. This, in turn, has been translated into an assessment of scenario impacts, local scale risk, and the nuancing effects of resilience on the outcomes. An exploration was carried out of the effectiveness of a range of retrofit strategies directed at addressing the residential buildings in our communities that contribute the most wind risk in South East Queensland. The outcome are expected to be a valuable resource for all the project partners and stakeholders in the areas of planning, preparation, response, recovery and strategic mitigation.</div>