Bob Cechet, Mark Edwards and John Holmes (2006) Severe wind hazard/vulnerability modelling workshop,Geoscience Australia, Canberra, December 1st 2005. Proceedings of the 12th AWES Wind Engineering Workshop, Queenstown, New Zealand, February 2nd & 3rd, 4pp

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.

The Bushfire CRC initiated in 2011 the project 'Fire & Impact Risk Evaluation - Decision Support Tool (F.I.R.E.-D.S.T)' involving Geoscience Australia, CSIRO, Bureau of Meteorology and University of Melbourne. The project is the largest of the Bushfire CRC's suite of projects and conducts research into the multiple aspects required for the computer simulation of bushfire impact and risk on the peri-urban and urban interface. This paper will provide an overview of the research directions for the project and our research progress. In particular we will summarise our progress in: - The development of a Bushfire Risk Assessment Framework, - The inclusion of detailed building information to improve exposure, - The inclusion of human factors and wind damage in determining building vulnerability to bushfires, - The new Bureau of Meteorology ACCESS Numerical Weather Prediction (NWP) system to provide high temporal and spatial resolution meteorology for input into the PHOENIX Rapidfire fire spread simulation model, - The development of very-high resolution local wind modifiers, - The changes made to the PHOENIX fire simulation system, - The development of an bushfire impact/damage subsystem, - The integration of the exposure, vulnerability, fire spread and impact systems to produce a cohesive research tool, and - Initial research on convection column and smoke plume dynamics. The team examined the effectiveness of this research by analysing numerous simulation scenarios. This paper will display the effectiveness of the research progress by providing one example of the comparison between the 2009 Black Saturday

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.

Severe wind is one of the major natural hazards in Australia. The main contributors to economic loss in Australia are tropical cyclones, thunderstorms and sub-tropical (synoptic) storms. Geoscience Australia's Risk and Impact Analysis Group (RIAG) is developing mathematical models to study a number of natural hazards including wind hazard. This study examines synoptic wind hazard under current and future climate scenarios using RIAG's synoptic wind hazard model. This model can be used in non-cyclonic regions of Australia (Region A in the Australian-New Zealand Wind Loading Standard; AS/NZS 1170.2:2002) which are dominated by synoptic and thunderstorm winds. The methodology to study synoptic wind hazard involves a combination of three models: - a statistical model (ie. a model based on observed data) to quantify wind hazard using extreme value distributions; - a technique to extract and process wind speeds from a high-resolution regional climate model (RCM), which produces gridded hourly 'maximum time-step mean' wind speed and direction fields; and - a Monte Carlo method to generate gust wind speeds from the RCM mean winds. Gust wind speeds are generated by a numerical convolution of the modelled mean wind speed distribution and a distribution of observed 'regional' gust factor. To illustrate the methodology, wind hazard calculations under current and future climate conditions for the Australian state of Tasmania will be presented. The results show increases in synoptic wind hazard in some parts of the state especially at the end of this century.

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. The Geoscience Australia's Risk and Impact Analysis Group (RIAG) is developing mathematical models to study a number of natural hazards including wind hazard. In this study, RIAG's wind hazard model for non-cyclonic regions of Australia (Region A in the Australian-New Zealand Wind Loading Standard; AS/NZS 1170.2(2010)) for both current and a range of projected future climate are discussed. The methodology involves a combination of 3 models: - A Statistical Model (ie. a model based on observed data) to quantify wind hazard using extreme value distributions. - A technique to extract and process wind speeds from a high-resolution regional climate model (RCM) which produces gridded hourly 'maximum time-step mean' wind speed and direction fields, and a - Monte Carlo method to generate gust wind speeds from the RCM mean winds. Gust wind speeds are generated by a numerical convolution of the mean wind speed distribution and a regional 'observed' gust factor. Wind hazard at a particular location is affected by the corresponding wind direction. In the last part of this paper a methodology to calculate wind direction multipliers over a region is presented. These multipliers are used to assess the actual wind hazard at the given location. To illustrate the methodology involved with the calculation of severe wind hazard, including the effect of wind direction, analysis over the Australian state of Tasmania will be presented (current and future climate).

Historical settlement patterns have resulted in Australia having most of its major city developments situated on the coastline. Storm tides are a major natural hazard for coastal regions. Severe storms and cyclones contribute 29 per cent of the total damage cost from natural hazards to the Australian community. In 1999 prices, this amounts to A$40 billion during the period 1967 to 1999 (including the cost of deaths and injuries). A storm surge is an increase in coastal water levels well above the normal high tide. If the storm surge is combined with daily tidal variation, the combined water level is called the storm tide. When the resulting storm tide exceeds the normal tidal range, local beach topography will dictate whether significant coastal inundation will occur.

Australia is exposed to a wide range of natural hazards, including earthquake, cyclone, landslide, flood, storm surge, severe wind, bushfire, coastal erosion, hail storm and drought. How each person will fare in the event of a natural hazard is influenced not just by exposure to infrastructure, but also by personal attributes, community support, access to resources and governmental management. This network of factors affecting social vulnerability to natural hazards, combined with the complex linkages found in cities and the behaviour of the hazard itself, all contribute to the development of a risk assessment.

One of the more important observations from the 1989 Newcastle earthquake in Australia was the spatial distribution of earthquake damage, which was strongly related to variability in near-surface regolith properties and their influence on ground-shaking (i.e. site response). This association between ground-shaking and sediment distribution is well recognised, but has not previously been investigated for much of Australia. In an effort to characterize the Australian regolith in terms of its ability to modify earthquake energy, this study develops a national site classification map of Australia for application in first order earthquake hazard and risk assessment. Site classes are assigned based on a method developed in California, which uses the relationship between geological material and the shear wave velocity of the upper 30 m (Vs30). The classification scheme is then adjusted to suit the Australian geological environment, by accounting for the presence of highly weathered in situ regolith commonly encountered in this generally stable tectonic setting. This methodology has been successfully tested using geophysical data from a variety of Quaternary sedimentary environments in the Newcastle, Sydney and Perth urban areas and from bedrock-dominated environments at a range of sites across Australia.

Results from an audit of 32 petroleum exploration wells in the Bass Basin have shown that approximately half of the wells in the basin were invalid tests due to off-structure drilling or mis-interpretation. Of the remaining wells, primary reasons for failure were lack of effective seal, timing, trap validity, lack of access to mature source rocks or reservoir problems. In parts of the basin the regional seal (Demons Bluff Shale) has undergone a period of structural inversion during the late Tertiary resulting in seal breach. Anticlinal closures of Eocene age were particularly affected, while structures located on fault-bounded basement highs were less affected, and provide the only fields within the basin. In the Yolla and White Ibis fields, access to mature source rocks was provided by large-displacement, non-sealing faults, that linked the upper EVG reservoirs with deeper source rocks. Traps without this conduit have as yet been unsuccessful. Sandy units within the Eastern View Group in the Pelican Trough are tight reservoirs that have good porosity but poor permeability. This is due to diagenetic effects that prohibited the creation of secondary porosity and permeability. Although identified risks within the basin can be minimised, the key to successful exploration will be finding traps that were in-place prior to the generation of hydrocarbons, but did not undergo significant Tertiary inversion.