risk
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A tropical cyclone (or hurricane in North America, typhoon in Asia) is an intense tropical low-pressure weather system where, in the southern hemisphere, winds circulate clockwise around the centre. Tropical cyclone development is complex, but researchers have identified three components of a tropical cyclone that make up the total cyclone hazard: strong winds, intense rainfall and induced ocean effects including extreme waves, currents, storm surge and resulting storm tide.
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Floods are estimated to be the most costly natural disaster in Australia. The average direct annual cost of flooding between 1967 and 1999 has been estimated at A$314 million (BTE 2001). Economic loss due to flooding varies widely from year to year and is dependent on a number of factors for example, flood severity and location. The most costly year for floods was 1974, with a total cost of A$2.9 billion (BTE 2001). Some major floods and their estimated cost in 1998 values (Agriculture and Resource Management Council of Australia and New Zealand, ARMCANZ 2000) include: <li>Brisbane floods, Summer 1974, A$700 million damage</li> <li>Victoria floods, Spring 1993, A$320 million damage</li> <li>Hunter River floods, 1955, A$500 million damage.</li> Flooding has a major impact on our communities. There have been ninety-nine recorded deaths from floods between 1967 and 1999 and 1019 recorded injuries (Bureau of Transport Economics, 2001). The impact of flooding be devastating, with the affects often extending beyond the zone of inundation, as can be seen in Figure 1. The floods in regional Queensland and NSW in 2001, for example, resulted in an increase in the cost of fruit and vegetables in Australia
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Geoscience Australia has developed a model to assess severe wind hazard for large-scale numerical model-derived grided data. The severe wind modelling approach integrates two models developed at Geoscience Australia: a) A statistical model based on observations which determines return periods (RP) of severe winds using Extreme Value distributions (EVD), and b) A model which extracts mean wind speeds from high resolution numerical models (climate simulations) and generates wind gust from the mean speeds using Monte Carlo simulation (convolution with empirical gust factors) This methodology is particularly suitable for the study of wind hazard over large regions, and is being developed to provide improved spatial information for the Australia/NZ Wind Loading Standard (AS/NZS 1170.2, 2002). The methodology also allows comparison of current and future wind hazard under changing climate conditions. To illustrate the characteristics and capabilities of the methodology, the determination of severe wind hazard for a high-resolution grid encompassing the state of Tasmania (south of the Australian continent) will be presented and discussed, considering both the current and a range of possible future climate conditions (utilising IPCC B1 & A2 emission scenarios).
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The seismicity of the Australian continent is low to moderate by world standards. However, the seismic risk is much higher for some types of Australian infrastructure. The legacy of older unreinforced masonry buildings, in particular, may contribute disproportionately to community risk. At 8:17am on the 20th April a Mw 5.0 earthquake shook Kalgoorlie. The resultant ground motion was found to vary markedly across the town with the older masonry building stock in the suburb of Boulder experiencing a greater shaking intensity than the corresponding vintage of buildings in the Kalgoorlie business district 4km away. The event has provided the best opportunity to examine the earthquake vulnerability of Australian buildings since the Newcastle Earthquake of 1989. This paper describes the event and the staged collaborative survey activity that followed. The initial reconnaissance team of two specialists captured street-view imagery of 12,000 buildings within Kalgoorlie using a vehicle mounted camera array developed by Geoscience Australia. This information subsequently informed a systematic population based building survey using PDA data collection units. The work was performed by a team of nine from the University of Adelaide, the University of Melbourne and Geoscience Australia. This paper describes the preliminary findings of the work and outlines proposed future research.
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This point dataset contains the Australian Coastal Maritime Navigation Aids including 'traditional-type' lighthouses and the newer solar powered automated lights.
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FIRE-DST is the largest of the projects within the extended Bushfire Cooperative Research Centre (BCRC). It is addressing the sub-theme of evaluating risk by developing a framework and computational methodology for evaluating the impacts and risks of extreme fire events on regional and peri-urban populations (infrastructure and people) applicable to the Australian region. The research is considering three case studies of recent extreme fires employing an ensemble approach (sensitivity analysis) which varies the meteorology, vegetation and ignition in an effort to estimate fire risk to the case-study fire area and adjacent region. Outcomes from recent extreme fires have demonstrated a need for a tool to assess future bushfire impacts and risk on regional and peri-urban communities. Such a tool would illustrate (map) bushfire impact and risk across the urban fringe and will also enable fire and land management authorities to develop and assess the effect of appropriate fire risk treatment options at local, regional and national levels. The tool would also characterise vegetation, extreme fire weather, firespread, smoke production and dispersion, and estimate the consequences of extreme fires on communities. As well as being validated using conditions pertaining at the time of the case study events, the tool will be used to explore alternative scenarios reflecting the sensitivity in ignition, fuel load and state, meteorology and fire spread, as well as alternative suppression strategies. Results from these scenario analyses and associated reports and papers will be communicated via the project website and through structured workshops.
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Climate change is expected to increase severe wind hazard in many regions of the Australian continent with consequences for exposed infrastructure and human populations. The objective of this study is to provide a nationally consistent assessment of wind risk under current climate and to provide preliminary indications of the effects (impact) of future hazard under several climate change scenarios. This is being undertaken by considering wind hazard, infrastructure exposure and wind vulnerability of infrastructure (residential buildings). The National Wind Risk Assessment (NWRA) will identify communities subject to high wind risk under present climate, and which will be most susceptible to any climate change related exacerbation of local wind hazard. While there is significant uncertainty on what the likelihood of extreme winds will be in the future, the understanding of current local wind hazard for the Australian region is also in need of improvement. Australian wind hazard is based on the statistical analysis of extreme wind observations and engineering judgement. Observations include peak 3-second gusts captured at about 30 meteorological measurement stations, mainly located at significant city and regional airports. These provide poor spatial texture with regard to wind hazard. This study is taking advantage of modelled wind hazard assessments (current climate) being developed at Geoscience Australia utilising separate techniques for the three main wind hazards: tropical cyclones; thunderstorms; and synoptic winds. A stochastic model based on observed and modelled cyclone tracks is used to obtain an understanding of cyclonic wind hazard, whilst two statistical approaches involving observed and modelled vertical instability and mean wind speed fields (via high-resolution regional climate model) are the basis for the thunderstorm and synoptic wind hazard.
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Macroseismic shaking intensity is a fundamental parameter for the development, calibration, and use in a variety of hazard maps as well as in empirical (direct) and semi-empirical (indirect) earthquake shaking loss methodologies. Macroseismic data also quantify damage from past and present events and facilitate communicating ground motion levels in terms of human experiences and incurred losses. The aim of this report is to summarize and recommend 'best practices' for the use of macroseismic intensity in conjunction with hazard maps (particularly ShakeMaps) and as input to associated loss models. The continued reliance on macroseismic intensity data dictates that ground motion prediction equations (GMPEs) alone are not always sufficient for estimating or constraining shaking hazards. Relations that allow direct estimation of intensity given an earthquake magnitude and distance, and those that convert ground motions to intensity (and vice versa) are required. Forward estimation of macroseismic intensities take two primary forms: 1) direct intensity prediction equations (IPEs), and 2) ground-motion-to-intensity conversion equations (GMICE). In addition, one can potentially better constrain historical ground motions at particular sites by employing intensity-to-ground-motion conversion equations (IGMCEs), though such equations are rare. Both the Global Earthquake Model (GEM) and Global ShakeMap (GSM) require advice and optimization in the state-of-the-art use of ground motion and intensity data. We provide background on the issues relating ground motions to intensities, directly predicting intensities, and offer insight into their uses.
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The 2004 Indian Ocean Tsunami raised the importance of tsunami as a significant emergency management issue in Australia. The Australian government responded by initiating a range of measures to help safeguard Australia from tsunami, in particular the Australian Tsunami Warning System (ATWS). In addition it is supporting fundamental research into understanding the tsunami risk to Australian communities. The Risk and Impact Analysis Group (RIAG) of Geoscience Australia achieves this through the development of computational methods, models and decision support tools for use in assessing the impact and risk posed by hazards. Together with support from Emergency Management Australia, it is developing a national tsunami hazard map based on earthquakes generated from the subduction zones surrounding Australia. These studies have highlighted sections of the coastline that appear vulnerable to events of this type. The risk is determined by the likelihood of the event and the resultant impact. Modelling the impacts from tsunami events is a complex task. The computer model ANUGA is used to simulate the propagation of a tsunami toward the coast and estimate the level of damage. A simplification is obtained by taking a hybrid approach where two models are combined: relatively simple and fast models are used to simulate the tsunami event and wave propagation through open water, while the impact from tsunami inundation is simulated with a more complex model. A critical requirement for reliable modelling is an accurate representation of the earth's surface that extends from the open ocean through the inter-tidal zone into the onshore areas. However, elevation data may come from a number of sources and will have a range of reliability.
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This booklet identifies different types of volcanoes, and the dangers associated when volcanic materials are ejected in an eruption. It explains the importance of why we should study volcanoes and the effects these eruptions have on the atmosphere and climate. It also identifies where volcanoes are located in Australia. Student activities are included.