In response to the devastating Indian Ocean Tsunami (IOT) that occurred on the 26th of December 2004, Geoscience Australia developed a framework for tsunami risk modelling. The outputs from this methodology have been used by emergency managers throughout Australia. For GA to be confident in the information that is being provided to the various stakeholders' validation of the model and methodology is required. While the huge loss of life from the tsunami was tragic, the IOT did provide a unique opportunity to record the impact of a tsunami on the coast of Western Australia. Eight months after the tsunami a post-disaster survey was conducted at various locations along the coast and maximum run-up was determined from direct observational evidence or anecdotal accounts. In addition tide gauges located in harbours along the coast also recorded the tsunami and provide a timeseries account of the wave heights and frequency of the event. This study employs the tsunami hazard modelling methodology used by Geoscience Australia (GA) to simulate a tsunami scenario based on the source parameters obtained from the Boxing Day earthquake of 2004. The model results are compared to observational evidence from satellite altimetry, inundation surveys and tide gauge data for Geraldton, a community on the Western Australian coast. Results show that the tsunami model provides good estimates of the wave height in deep water and also run up in inundated areas and it importantly matches the timing of the first wave arrivals. However the model fails to reproduce the timeseries data of wave heights observed by a tide gauge in Geraldton harbour. The model does however replicate the occurrence of a late arriving (16 hrs after first arrival) wave packet of high frequency waves. This observation is encouraging since this particular wave packet has been noted elsewhere in the Indian Ocean and caused havoc in harbours many hours after the initial waves had arrived and dissipated.

A selection of images and short animations explaining key aspects of the 2004 Indian Ocean/ Sumatra tsunami, revised and issued for release to the media and other interested organisations on the tenth anniversary of the disaster. This selection updates existing resources previously released by Geoscience Australia.

Potential impacts of climate change present significant challenges for land use planning, emergency management and risk mitigation across Australia. Even in current climate conditions, the Rockhampton Regional Council area is subject to the impacts of natural hazards, such as bushfires, floods, and tropical cyclones (extreme winds and storm surge). All of these hazards may worsen with climate change. To consider future climate hazard within council practices, the Rockhampton Regional Council received funding from the National Climate Change Adaptation Research Grants Program Project for a project under the Settlements and Infrastructure theme. This funding was provided to evaluate the ability of urban planning principles and practices to accommodate climate change and the uncertainty of climate change impacts. Within this project, the Rockhampton Regional Council engaged Geoscience Australia to undertake the modelling of natural hazards under current and future climate conditions. Geoscience Australia's work, within the broader project, has utilised natural hazard modelling techniques to develop a series of spatial datasets describing hazards under current climate conditions and a future climate scenario. The following natural hazards were considered: tropical cyclone wind, bushfire, storm tide, coastal erosion and sea-level rise. Outputs of this project include a report, hazard maps and digital spatial data.

We have developed models for the prediction of bedrock ground motion response spectra in several regions of Australia. In Eastern Australia, we developed models for the Paleozoic Lachlan Fold Belt, and the Sydney Basin that lies within it, and in Western Australia we developed models for the Yilgarn Craton and the adjacent Perth Basin. The models are based on the broadband simulation of accelerograms using regional crustal velocity models and earthquake source scaling relations. For both the Lachlan Fold Belt and Yilgarn regions, we used comparison of synthetic seismograms with the recorded seismograms of small earthquakes to test and modify regional crustal velocity models. In Western Australia, we used the rupture models of the 1968 Mw 6.6 Meckering earthquake and the 1988 Mw 6.25, 6.4 and 6.5 Tennant Creek earthquakes to constrain the scaling relationship between seismic moment and rupture area. Other aspects of the source scaling relations were derived from our scaling relations for earthquakes in eastern North America (Somerville et al., 2001). In eastern Australia, the data available for historical earthquakes are insufficient to constrain earthquake scaling relations, so we have used the relations for Western Australia as well as the relations for the western United States (Somerville et al., 1999). We generated suites of broadband ground motion time histories using these source scaling relations and crustal structure models. These ground motion simulations were used to generate ground motion prediction models for each region. The ground motion models have been compared with the model of Liang et al. (2008) for Western Australia, with models for Eastern North America including Atkinson and Boore (2006), Somerville et al (2001), and Toro et al (1997), and with the NGA models.

The Australian Flood Studies Database is available on line by Geoscience Australia via the Australian Flood Risk Information Portal. The database provides metadata on Australian flood studies and information on flood risk with a digital version where available. The purpose of the document is to guide new users in data entry and uploading of flood studies to a level acceptable for inclusion in the database.

Developed in consultation with Emergency Management Australia (EMA), this kit defines and maps major hazards affecting Australia - earthquakes, tsunamis, landslides, volcanoes, severe storms, cyclones, bushfires, floods and droughts. This kit helps students and teachers recognise risks from different natural hazards and the practical steps we can all take to reduce their effects. The Australian Natural Hazards Education Map Kit contains: - eight colour A3 poster maps with descriptive text - eight blackline A4 map masters - background information on each hazard - student activities - Emergency Management Australia hazard action cards Suitable for primary years 5-6 and secondary years 7-8.

As part of the Australian Tsunami Warning System Project (2005-09), the Attorney-General's Department funded Geoscience Australia to develop the national offshore Probabilistic Tsunami Hazard Assessment (PTHA). This assessment could then be used by Australian emergency managers in understanding the tsunami hazard to Australia. The national offshore PTHA considers the tsunami hazard posed to the entire Australian coast by tsunami caused by subduction zone earthquakes in the Indian and Pacific Oceans. These regions are known to have produced major tsunamigenic events External site link in recorded history and are the most likely sources of future events. The hazard maps are defined at a bathymetry water depth contour of 100m offshore. This normally falls outside of the Great Barrier Reef or other reef systems. The 100m depth contour is chosen because: Estimating the tsunami closer to the coast requires high resolution bathymetric data which does not always exist for the entire coast estimating the tsunami closer to the coast is a more computational and time intensive task. These maps help to identify the areas which are most likely to be at risk to damaging tsunami waves. However, they cannot be used directly to infer how far a tsunami will inundate onshore (inundation extent), how high above sea level they will reach on land (run-up), the extent of damage or any other onshore phenomena. To estimate the onshore tsunami impact, detailed bathymetry and topography of the specific region concerned is required for input to a detailed inundation model. The catalogue of tsunami events used to derive the national offshore PTHA can be used by emergency managers, researchers and individuals however to develop detailed inundation models at any onshore location.

This data set is the Earthquake Hazard Risk Contour Map for Australia based on earthquake measurements taken from the Geoscience Australia Earthquake Database. It shows the acceleration coefficient (a) 10 percent chance of being exceeded in the next 50 years. Thus a value of 0.05 as an example means that in any 50 year period, there is a 90% chance that the peak ground acceleration will not exceed 0.05. Where peak ground acceleration is a dimensionless coefficient of acceleration that is used by civil engineers to estimate forces on structures. High values of this calculation represent higher risk areas of earthquake occurrence.

This is an article summarising of the earthquake hazard work for 2009-10 for the society's newsletter.

This document presents a new set of earthquake hazard maps for consideration in the next revision of the earthquake loading code AS1170.4 "Structural design actions: Part 4 Earthquake actions in Australia". The earthquake catalogue used here includes events up until 2011. It is a combined version of several catalogues provided by external agencies. This represents the most complete catalogue of earthquakes compiled for Australia. The catalogue is more consistent through conversion of various magnitude measurements into a 'pseudo ML' scale. A systematic logic is used to select preferred magnitude types. Aftershocks, foreshocks and mine blasts have been identified and the declustered catalogue used here is cleaner than any previous Australian catalogue. Earthquake source zones applied in the hazard map use a unique combination of three different layers, which capture seismic characteristics at sub-national, regional and high-activity point scales. The map is one of the first in the world to apply a semi-quantitative measure of Mmax for majority of the source zones in the map. We apply recently developed ground motion prediction equations based on modern methods and data. These equations were used to calculate the ground motion at a range of response spectral accelerations, rather than just calculating the hazard for peak ground acceleration (PGA). A suite of maps is calculated using GA's Earthquake Risk Model (EQRM). The EQRM is open-source, allowing the results to be tested or modified independently. The final 2012 Australian earthquake hazard maps for a range of return periods and response spectral periods are presented herein.