risk analysis
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This paper discusses two of the key inputs used to produce the draft National Earthquake Hazard Map for Australia: 1) the earthquake catalogue and 2) the ground-motion prediction equations (GMPEs). The composite catalogue used draws upon information from three key catalogues for Australian and regional earthquakes; a catalogue of Australian earthquakes provided by Gary Gibson, Geoscience Australia's QUAKES, and the International Seismological Centre. A complex logic is then applied to select preferred location and magnitude of earthquakes depending on spatial and temporal criteria. Because disparate local magnitude equations were used throughout Australia, we performed first order magnitude corrections to standardise magnitude estimates to be consistent with the attenuation factors defined by contemporary local magnitude ML formulae. While most earthquake magnitudes do not change significantly, our methodology can result in reductions of up to one magnitude unit in certain cases. Subsequent ML-MW (moment magnitude) corrections were applied. The catalogue was declustered using a magnitude dependent spatio-temporal filter. Previously identified blasts were removed and a time-of-day filter was developed to further deblast the catalogue. Secondly, a suite of candidate GMPEs were systematically tested against 5% damped response spectra recorded from Australian earthquakes in eastern and Western Australia, respectively. Since many GMPEs are developed for earthquakes larger than approximately MW 5.0, much of the data recorded in Australia is below the magnitude threshold prescribed by these equations. Nevertheless, where necessary, we extrapolate these equations to lower magnitudes to test the general applicability of the GMPEs for different source zones across Australia. The relative weights of the GMPEs for the draft national hazard model were initially determined objectively by the authors using these analyses as a basis. Final GMPE weights will be assigned through consultation with key stakeholders through the AEES.
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11-5519 Metropolitan Manilla (Philippines). Philippine GIS data-sets should arrive from the source on the 15th of July, 2011. GAV will process the data, and produce a short movie. The movie will reveal the 17 town halls of the greater metro Manilla; and outline the fault line, as well as earthquake affected areas, flood affected areas and cyclone affected areas. This movie is for the Philippine Govt. via Ausaide, and will include photographs of Philippine nationals assisting in disaster reduction work. The aquired data-sets will be stored on the GA data store, where access can be gained through communication with Luke Peel - GEMD National Geographic Information Section, Geoscience australia.
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In order to calibrate earthquake loss models for the U.S. Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER) system, two databases have been developed: an Atlas of ShakeMaps and a catalog of human population exposures to moderate to strong ground shaking (EXPO-CAT). The full ShakeMap Atlas currently contains over 5,600 earthquakes from January 1973 through December 2007, with almost 500 of these maps constrained by instrumental ground motions, macroseismic intensity data, community internet intensity observations, and published earthquake rupture models. The catalog of human exposures is derived using current PAGER methodologies. Exposure to discrete levels of shaking intensity is obtained by merging Atlas ShakeMaps with a global population database. Combining this population exposure dataset with historical earthquake loss data provides a useful resource for calibrating loss methodologies against a systematically-derived set of ShakeMap hazard outputs. Two applications of EXPO-CAT are illustrated: i) a simple objective ranking of country vulnerability to earthquakes, and; ii) the influence of time-of-day on earthquake mortality. In general, we observe that countries in similar geographic regions with similar construction practices tend to cluster spatially in terms of relative vulnerability. We find only limited quantitative evidence to suggest that time-of-day is a significant factor in earthquake mortality. Finally, we combine all the Atlas ShakeMaps to produce a global map of the peak ground acceleration (PGA) observed in the past 35 years, and compare this composite ShakeMap with existing global hazard models. In general, these analyses suggest that existing global and regional hazard maps tend to overestimate hazard.
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This is a short and informative 3.3 minute movie for the Engineering, Economics and Exposure Project - NEXIS Development for DCCEE - late 2010. It is a promotional movie that demonstrates NEXIS capabilities, and explains how NEXIS will be benefitial to the NEXIS stakeholder. This movie may also go onto the web, where it's purpose is to convince the public that NEXIS is a worthwhile investment in Australia's future.
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A model to assess severe wind hazard using climate-simulated wind speeds has been recently completed at Geoscience Australia. The model can calculate return period of wind speeds over a given region considering current as well as future climate conditions. The winds extracted from the climate simulations are winds at 10m height over open terrain. In hazard studies it is important however, to refer the wind speeds to the characteristics of the given location in order to calculate the actual severe wind hazard at the regional level. This is achieved by multiplying the generic wind hazard by a number of wind multipliers. One of those multipliers is wind direction. The wind direction multiplier recognises the prevailing direction of the strongest winds and affects the wind hazard accordingly. Lower wind hazard would correspond to the direction of low wind speeds. In practical applications engineers calculate the wind load in structures by multiplying the design wind speeds recommended by the Australian/NZ standards for wind loading in structures (AS/NZS 1170.2:2010) by some generic multipliers also given in the standards. The multipliers have been developed considering a number of Bureau of Meteorology (BoM) weather recording stations at particular locations in Australia; this method cannot capture the actual regional characteristics in such a vast country like Australia. In this paper we propose a new methodology for calculation of wind direction multipliers based on wind speeds and direction extracted from climate simulations. Our method allows a more realistic assessment of the wind direction multiplier at a particular region.
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The sensitivity of the Jaiswal and Wald (Earthq. Spectra, 2010) empirical earthquake fatality model is evaluated relative to the model space for a suite of macroseismic intensity prediction methods. The relative difference between intensity prediction methods is shown through the use of self-organizing maps to visualize high-dimensional ground shaking data in a two-dimensional space. Among all the macroseismic intensity prediction methods evaluated, there is significant variability in the resulting loss estimates for an earthquake of given source parameters with losses being most sensitive to those intensity models that predict high near-source ground shaking. Because the empirical fatality models evaluated herein are based on a consistent suite of ground-motion model inputs, application of the fatality models with other intensity prediction methods may result in undesirable outcomes. Consequently, it is recommend that empirical loss models be calibrated directly with hazard inputs used in the proposed loss assessment methodology.
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Full Version - shows orthographic and fly-through sequence for each of 5 scenarios with a combined max. inundation outline fly-through at end. Description. - Tropical Cyclone Alby passed close to the southwest corner of West Australia on April 4th 1978. Large waves and a storm surge generated by the northerly winds caused substantial coastal erosion along the Lower West coast particularly in the Geographe Bay area. Low-lying areas at Bunbury and Busselton were flooded, forcing the evacuation of many homes including the Bunbury Nursing Home. An approximate 1.1 m storm surge at Busselton caused the tide to peak at 2.5 m about 1 m above the highest astronomical tide. The Busselton Jetty was severely damaged. At Fremantle the surge was about 0.6 m causing a high tide of 1.8 m, about 0.5 m above the highest astronomical tide. [From BOM - http://www.bom.gov.au/weather/wa/cyclone/about/perth/alby.shtml - Retrieved 21/01/2010] This movie displays the results of a number of simulated storm surge events caused by an equivalent storm to Tropical Cyclone Alby on the current built terrain of Mandurah, and projected 2100 coastline with 0.5, 0.8 and 1.1m rises in sea level. Scenario A TC Alby equivalent at current sea level Scenario B Worst case TC Alby equivalent with current sea level Scenario C Worst case TC Alby equivalent in 2100 with 0.5m sea level rise Scenario D Worst case TC Alby equivalent in 2100 with 0.8m sea level rise Scenario E Worst case TC Alby equivalent in 2100 with 1.1m sea level rise
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11-5413 The Probabilistic Volcanic Ash - Hazard Map movie describes how you construct a probabilistic hazard map for volcanic ash, using an example scenario from GA's volcanic ash modelling work in West Java, Indonesia. The target audience is other govt. agencies both national and international, and the general public. The 3.3 minute movie uses 3D Max animations and 2D affects, has narration and production music. The narration will also be done in Bahasa Indonesian, at a later date.
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Geoscience Australia is currently undertaking the process to update the Australian National Earthquake Hazard Map using modern methods and an extended, more complete catalogue of Australian earthquakes. This map is a key component of Australia's earthquake loading code. The characterisation of strong ground-shaking using Ground-Motion Prediction Equations (GMPEs) underpins any earthquake hazard assessment. Recently there have been many advances in ground-motion modelling for active tectonic regions. However, the challenge for Australia - as it is for other stable continental regions - is that there are very few ground-motion recordings from large-magnitude earthquakes with which to develop empirically-based GMPEs. Consequently, there is a need to consider other numerical techniques to develop GMPEs in the absence of recorded data. Recently published Australian-specific GMPEs, which employ these numerical techniques, are now available and these will be integrated into Geoscience Australia's future hazard outputs. <p> This paper addresses several fundamental aspects related to ground-motion in Australia that are necessary to consider in the update of the National Earthquake Hazard Map, including: 1) a summary of recent advances in ground-motion modelling in Australia; 2) a comparison of Australian GMPEs against those commonly used in other stable continental regions; and 3) the impact of updated attenuation factors on local magnitudes in Australia. Specific regional and temporal aspects of magnitude calculation techniques across Australia and its affects on the earthquake catalogue will also be addressed. </p>
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Effective disaster risk reduction is founded on knowledge of the underlying risk. While methods and tools for assessing risk from specific hazards or to individual assets are generally well developed, our ability to holistically assess risk to a community across a range of hazards and elements at risk remains limited. Developing a holistic view of risk requires interdisciplinary collaboration amongst a wide range of hazard scientists, engineers and social scientists, as well as engagement of a range of stakeholders. This paper explores these challenges and explores some of the common and contrasting issues sampled from a range of applications addressing earthquake, tsunami, volcano, severe wind, flood, and sea-level rise from projects in Australia, Indonesia and the Philippines. Key issues range from the availability of appropriate risk assessment tools and data, to the ability of communities to implement appropriate risk reduction measures. Quantifying risk requires information on the hazard, the exposure and the vulnerability. Often the knowledge of the hazard is reasonably well constrained, but exposure information (e.g., people and their assets) and measures of vulnerability (i.e., susceptibility to injury or damage) are inconsistent or unavailable. In order to fill these gaps, Geoscience Australia has developed computational models and tools which are open and freely available. As the knowledge gaps become smaller, the need is growing to go beyond the quantification of risk to the provision of tools to aid in selecting the most appropriate risk reduction strategies (e.g., evacuation plans, building retrofits, insurance, or land use) to build community resilience.