The tectonic origin, paleoearthquake histories and slip rates of six normal faults (referred to here as the Rahotu, Oaonui, Kina, Kiri, Ihaia and Pihama faults) have been examined for up to ~26 kyr within the Taranaki Rift, New Zealand. A minimum of 13 ground-surface rupturing paleoearthquakes have been recognised on four of the faults using analysis of displaced late Quaternary stratigraphy and landforms. These data, in combination with 21 new radiocarbon dates, constrain the timing, slip and magnitude of each earthquake. The faults have low throw rates (~0.1-0.8 mm/yr) and appear to be buried near the Mt Taranaki volcanic cone. Recurrence intervals between earthquakes on individual faults typically range from 3-10 kyr (average ~ 6 kyr), with slip/earthquake ranging from ~0.3-1.5 m (average ~0.7 m). Recurrence intervals and slip/earthquake typically vary by up to a factor of three on individual faults, with only the Oaonui Fault displaying near-characteristic slip (of about 0.5 m) during successive earthquakes. The timing and slip of earthquakes on individual faults appear to have been interdependent, with each event possibly relieving stress and decreasing the likelihood of additional earthquakes across the system. Earthquake magnitudes are estimated to be M 6.5-6.7. The dating resolution of paleoearthquakes is generally ±1-2 kyr and is presently too imprecise to test the temporal relations between seismic events and either volcanic eruptions or lahars formed by debris avalanches during cone collapse. It is unlikely, however, that formation of the ~7.8 kyr Opua Formation lahar was triggered by a large earthquake on the Rahotu, Oaonui or Kina faults which, of the faults studied, are farthest from the Mt Taranaki volcanic cone.

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

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).

We report on an assessment of severe wind hazard across the Australian continent, and severe wind risk (quantified in annualised losses due to severe wind damage) in built up areas, based on innovative modelling techniques and application of the National Exposure Information System (NEXIS). A combination of tropical cyclone, synoptic and thunderstorm wind hazard estimates is used to provide a revised estimate of the severe wind hazard across Australia. The hazard modelling techniques developed in this assessment utilise both 'current-climate' and also simulations forced by IPCC SRES climate change scenarios, which have been employed to determine how the wind hazard will be influenced by climate change. We have also undertaken a national assessment of localised wind speed modifiers including topography, terrain and built environment. It is important to account for these effects in assessment of risk as it is the local wind speed that causes damage to structures. The effects of the wind speed modifiers are incorporated through a statistical modification of the regional wind speed. The results from this current climate hazard assessment are compared with the hazard based on the existing understanding as specified in the Australian/New Zealand Wind Loading Standard (AS/NZS 1170.2, 2002). Regions are mapped where the design wind speed depicted in AS/NZS 1170.2 is significantly lower than 'new' hazard analysis. These are regions requiring more immediate attention regarding the development of adaptation options including consideration by the wind loading standards committee for detailed study in the context of the minimum design standards in the current building code regulations. Considering future climate scenarios, the Tasmanian region is used to illustrate where the wind loading standard becomes inadequate, and where retrofitting is indicated as a viable adaptation option at a specified future time. The cost/benefit analysis techniques used will be demonstrated.

The paper presents a methodology developed at Geoscience Australia to analyse the impact of tropical cyclone (TC) hazard on communities in northern Australia. This work was carried out for the Garnaut Climate Change Review commissioned by Australia's State and Territory Governments. The Review examined the impacts of, and possible policy responses to, climate change on the Australian economy The study focuses on the maximum potential intensity (MPI) of the wind hazard. This sets a thermodynamic, theoretical upper limit for the distribution of TC intensities given a vertical temperature and humidity profile and given location. Storm surge impacts were developed using a simple relationship between TC intensity and storm surge height and adopting the IPCC global mid-point sea-level rise predictions. We consider the impact on residential building stock of severe wind and storm surge hazards associated with a number of IPCC climate change scenarios. Changes in residential building stock, for over 500 coastal statistical local areas (SLA's) from Southeast Queensland anticlockwise to Perth, were forecast using Australian Bureau of Statistics population projections through to 2100. A Probable Maximum Loss (PML) curve for each study region was obtained. The average annual cost to the region due to exposure to tropical cyclones across a 5000 year period or 'annualised losses' were evaluated for each study region. Expressing the annualised loss as a percentage of total reconstruction demonstrates the intensity of the risk to the studied community not so evident in simple dollar loss figures. We show the projected population, especially the drift to coastal locations in Queensland, is significant in determining the damage associated with possible future cyclone threat.

Stochastic finite-fault ground-motion prediction equations (GMPEs) are developed for the stable continental region of southeastern Australia (SEA). The models are applicable for horizontal-component ground motions for earthquakes 4.0 <= MW <= 7.5 and distances less than 400 km. The models are calibrated with updated source and attenuation parameters derived from SEA ground-motion data. Careful analysis of well-constrained earthquake stress parameters indicates a dependence on hypocentral depth. It is speculated that this is the effect of an increasing crustal stress profile with depth. However, rather than a continuous increase, the change in stress parameter appears to indicate a discrete step near 10 km depth. Average stress parameters for SEA earthquakes shallower and deeper than 10 km are estimated to be 23 MPa and 50 MPa, respectively. These stress parameters are consequently input into the stochastic ground-motion simulations for the development of two discrete GMPEs for shallow and deep events. The GMPEs developed estimate response spectral accelerations comparable to the Atkinson and Boore (BSSA, 2006) GMPE for eastern North America (ENA) at short rupture distances (less than approximately 100 km). However, owing to higher attenuation observed in the SEA crust (Allen and Atkinson, BSSA, 2007), the SEA GMPEs estimate lower ground-motions than ENA models at larger distances. The response spectral models are validated against moderate-magnitude 4.0 <= MW <= 5.3 earthquakes from eastern Australia. Overall the SEA GMPEs show low median residuals across the full range of period and distance. In contrast, Eastern North American models tend to overestimate response spectra at larger distances. Because of these differences, the present analysis justifies the need to develop Australian-specific GMPEs where ground-motion hazard from a distant seismic source may become important.

This paper is an introduction to the two AJEM Special Issues on risk assessment. The role of risk assessment in emergency management in Australia is firmly established and much progress has been made in utilising risk modelling tools and supporting data to develop new information on risk for some hazards. Significant further work is required to reach an understanding of all hazards risks nationally.

Severe wind accounts for about 40 percent of the total number of buildings damaged by natural disasters in Australia during the 20th Century. Climate change has the potential to significantly affect severe wind hazard and the resulting level of economic loss. We describe a computational framework that has been developed to quantify both the wind hazard and risk due to severe winds. The nationally consistent assessment of severe wind hazard and risk (residential buildings only) is based on innovative modeling techniques, heuristic wind vulnerability assessments and application of Geoscience Australia's National Exposure Information System (NEXIS). We have applied new modelling and analysis techniques to develop a revised understanding of the regional wind hazard across Australia. This modelling has enabled the development of a wind hazard map for the Australian region. Regional wind hazard has been assessed by utilising statistical-parametric models, dynamical downscaling and spatial interpolation techniques allowing the derivation of estimates of wind hazard from three different phenomena - tropical cyclones, thunderstorms and synoptic storms. Across much of the interior of the country, the revised estimates of regional wind speeds are comparable to the regional wind speeds specified in the existing Australian - New Zealand wind loading standard (AS/NZS 1170.2 2010), generally to within 10 percent for the design wind speeds (500-year return period gust wind hazard). The regional wind speeds derived in AS/NZS 1170.2 were determined from analysis of long-term records (observations) of daily maximum gust wind speeds.