risk assessment
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The tragic events of the Indian Ocean tsunami on 26 December 2004 highlighted shortcomings in the alert and response systems for tsunami threats to Western Australia's (WA) coastal communities. To improve community awareness and understanding of tsunami hazard and potential impact for Western Australia, the Fire and Emergency Services Authority of WA (FESA) established a collaborative partnership with GA in which science and emergency management expertise was applied to identified communities.
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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.
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Tropical cyclones, thunderstorms and sub-tropical storms can generate extreme winds that can cause significant economic loss. Severe wind is one of the major natural hazards in Australia. In this study, regional return period wind gust hazard (10 metre height over open terrain) is determined using a new methodology developed by Geoscience Australia over the past 3 years. The methodology developed for severe wind hazard (3-second peak gust) involves a combination of 3 models: - A Statistical Model (ie. data-based model) to quantify wind hazard using extreme value distributions. - A Monte Carlo method to calculate severe wind hazard produced by gust wind speeds using results from the Statistical Model. The method generates synthetic wind gust speeds by doing a numerical convolution of mean wind speeds and gust factors. - A high-resolution regional climate model (RCM) which produces gridded hourly 'maximum time-step mean- wind speed and direction fields. Area-averaged measurements from the RCM are 'corrected' for point measurement exposure by calibration with existing measurements. To assess model accuracy severe wind hazard return period levels (50, 100, 200, 500, 1000 and 2000 years) were determined for a number of locations where a long observation record is available. Comparisons are made between observational and RCM-generated return period of gust speeds; and also with the Australian/New Zealand wind loading standards (AS/NZS 1170.2, 2002).
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Cliff Head is the only producing oil field in the offshore Perth Basin. The lack of other exploration success has lead to a perception that the primary source rock onshore (Triassic Kockatea Shale) is absent or has limited generative potential. However, recent offshore well studies show the unit is present and oil prone. Multiple palaeo-oil columns were identified within Permian reservoir below the Kockatea Shale regional seal. This prompted a trap integrity study into fault reactivation as a critical risk for hydrocarbon preservation. Breach of accumulations could be attributed to mid Jurassic extension, Valanginian breakup, margin tilt or Miocene structuring. The study focused on four prospects, covered by 3D seismic data, containing breached and preserved oil columns. 3D geomechanical modelling simulated the response of trap-bounding faults and fluid flow to mid Jurassic-Early Cretaceous NW-SE extension. Calibration of modelling results against fluid inclusion data, as well as current and palaeo-oil columns, demonstrates that along-fault fluid flow correlates with areas of high shear and volumetric strains. Localisation of deformation leads to both an increase in structural permeability promoting fluid flow, and the development of hard-linkages between reactivated Permian reservoir faults and Jurassic faults producing top seal bypass. The main structural factors controlling the distribution of permeable fault segments are: (i) failure for fault strikes 350??110?N; (ii) fault plane intersections generating high shear deformation and dilation; and (iii) preferential reactivation of larger faults shielding neighbouring structures. These results point to a regional predictive approach for assessing trap integrity in the offshore Perth Basin.
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A review of the methods employed to collect 'buildings specific field data' following the impact of Tropical Cyclone Larry (March 2006) resulted in a plan to build a vehicular mounted rapid data inventory collection system to compliment post disaster surveys. The system assists to overcome issues related to restricted access, poor weather and difficult working conditions. The ability to quickly collect comprehensive information that is highly critical for both damage assessment and vulnerability model validation reduces assessment errors caused by rapid clearing of debris and repairs following the disaster, along with the use of tarpaulins which often obscure the level of damage viewed from the street. RICS consists of four 5-Megapixel Ethernet cameras attached to a tripod mounted on a vehicle, a GPS device and software written in C++. The images are compressed in jpeg format 'on-the-fly' and displayed in a Graphical User Interface (GUI) along with GPS location, bearing and speed. An additional display window shows the street-directory (UBD) roadmap and a GPS tracklog. Hot keys for instant damage assessment marking location and damage levels have been programed into the GUI. All images are geo-referenced and stored in a database.
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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 (re-turn period impact and risk expressed as annualized loss) of future hazard under several climate change scenarios. This is being undertaken by separately considering wind haz-ard, infrastructure exposure and the wind vulnerability of infrastructure (residential build-ings only). The National Wind Risk Assessment (NWRA), when it reports in December 2010, will identify communities subject to high wind risk under present climate, and also those communities which will be most susceptible to any climate change related exacer-bation of local wind hazard, requiring an adaptation response. The purpose of this paper is to present details of the methodology being utilised for the NWRA.
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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.
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Forest fires or bushfires, as they are called in Australia, are one of the major hazards facing the Australian continent. Chen (2004) rated bushfires as the third largest cause of building damage in Australia during the 20th century. Most of this damage was due to a few extreme bushfire events. The worst of these extreme events, and one of the worst natural disasters in Australian history, occurred in February 2009 when 173 people died and over 2000 houses were destroyed in the Victorian bushfires known as 'Black Saturday' (Bushfire CRC 2009). This study is focused on determining the bushfire hazard associated with communities that are located some distance from the nearest meteorological observing. Further assessment of the bushfire risk to communities can be achieved through the association of bushfire hazard (in the form of return period FFDI) with empirical house loss (Blanchi et al. 2010). In Sanabria et al (2012) we assess the impact of climate change on bushfire hazard using high resolution climate simulations. This study shows that the best interpolation results can be obtained by using a combination of random forest and inverse distance weighting. The interpolated maps using this combination showed physically plausible results and gave the smallest prediction errors.
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The tectonic setting of Australia has much in common with North America east of the Rocky Mountains because stable continental crust makes up the whole continent. The seismicity is still sufficient to have caused several damaging earthquakes in the past 50 yr. However, uncertainties in the earthquake catalogue limit the reliability of hazard models. To complement traditional hazard estimation methods, alternative methods such as paleoseismic, geodynamic numerical models and high-resolution global positioning system (GPS) are being investigated. Smoothed seismicity analysis shows that seismic recurrence varies widely across Australia. Despite the limitations of the catalogue, comparisons of regional strain rates calculated from the seismicity are consistent with data derived from geodetic techniques. Recent paleoseismic studies, particularly those examining high-resolution digital elevation models, have identified many potential prehistoric fault scarps. Detailed investigation of a few of these scarps suggests that the locus of strain release is migratory on a time scale an order of magnitude greater than the instrumental seismic catalogue, consistent with Australia's low-relief landscape. Numerical models based on the properties of the Australian plate provide alternative constraints on long-term crustal deformation. Two attenuation models for Australia have recently been developed. Because Australiais an old, deeply weathered continent that has experienced little Holocene glaciation, it has very little material comparable to North American "hard rock" site classification. The combination of relatively low attenuation crust under widespread thick weathered regolith makes the use of ground-motion and site response models derived from Australian data vital for Australian hazard assessment. Risk modeling has been used to assess sensitivities associated with variations in both source and ground-motion models. Systematic analyses allow the uncertainty in these models to be quantifi ed. Uncertainty in most input models contributes a 30%-50% variation in the predicted loss. Where a city lies in a thick sedimentary basin, such as Perth, uncertainties in the behavior of the basin can result in a 500% variation in predicted loss.
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This framework is a reference for individuals and agencies involved in bushfire risk assessment in Australia who seek to improve information on bushfire risk from quantitative methods compared to qualitative methods. It is aimed at bushfire researchers and risk managers in fire, planning and related agencies. Computational bushfire risk assessment is in an early stage of development in Australia. It is an opportune time to establish a framework sufficiently broad that it will accommodate pre-existing and new methods to assess bushfire risk while encouraging innovation. Current methods for assessing bushfire risk in Australia use different terminologies and approaches, and application of an overarching framework improves the potential to compare methods and confidence in comparing results between studies.