The development of the Indian Ocean Tsunami Warning and mitigation System (IOTWS) has occurred rapidly over the past few years and there are now a number of centres that perform tsunami modelling within the Indian Ocean, both for risk assessment and for the provision of forecasts and warnings. The aim of this work is to determine to what extent event-specific tsunami forecasts from different numerical forecast systems differ. This will have implications for the inter-operability of the IOTWS. Forecasts from eight separate tsunami forecast systems are considered. Eight hypothetical earthquake scenarios within the Indian Ocean and ten output points at a range of depths were defined. Each forecast centre provided, where possible, time series of sea-level elevation for each of the scenarios at each location. Comparison of the resulting time series shows that the main details of the tsunami forecast, such as arrival times and characteristics of the leading waves are similar. However, there is considerable variability in the value of the maximum amplitude (hmax) for each event and on average, the standard deviation of hmax is approximately 70% of the mean. This variability is likely due to differences in the implementations of the forecast systems, such as different numerical models, specification of initial conditions, bathymetry datasets, etc. The results suggest that it is possible that tsunami forecasts and advisories from different centres for a particular event may conflict with each other. This represents the range of uncertainty that exists in the real-time situation.

The aim of this document is to provide the Fire and Emergency Services Authority of Western Australia (FESA) with a preliminary assessment of tsunami risk to a number of communities in South West WA. This assessment follows the preliminary assessment of tsunami impact for six North West Shelf communities and probabilistic tsunami hazard assessment for Western Australia which described the chance of a given tsunami wave height at the 50m contour being exceeded.

The study of palaeotsunamis preserved in the sedimentary record has developed over the past three decades to a point where the criteria used to identify these events range from well-tested and accepted to new methods yet to receive wide application. In this paper we review progress with the development of these criteria and identify opportunities for refinements and for extending their application to new settings. The emphasis here is on promoting the use of multiple proxies, selected to best match the context of the site or region of interest. Ultimately, this requires that palaeotsunami research must be a multidisciplinary endeavour and indeed, extend beyond the geological sciences of sedimentology and stratigraphy to include knowledge and approaches from field such as archaeology, anthropology and sociology. We also argue that in some instances, despite the use of multiple proxies, the ev

We present the first national probabilistic tsunami hazard assessment (PTHA) for Indonesia. This assessment considers tsunami generated from earthquakes near-field sources around Indonesia as well as regional and far-field sources, to define the tsunami hazard at the coastline. The methodology is based on the established monte-carlo approach to probabilistic seismic hazard assessment (PSHA) and has been adapted to tsunami. The earthquake source information is primarily based on the recent Indonesian National Seismic Hazard Map developed by Team-9 and included a consensus-workshop with Indonesia's leading tsunami and earthquake scientists to finalise the input parameters. Results are presented in the form of tsunami hazard maps showing the expected tsunami height at the coast for a given return period (100, 500 and 2500 years) , and also as tsunami probability maps showing the probability of exceeding 0.5m and 3.0m at the coast, which define the thresholds for different tsunami warning levels in the Indonesian Tsunami Early Warning System (Ina-TEWS).

Keynote presentation to cover * the background to tsunami modelling in Australia * what the modelling showed * why the modelling is important to emergency managers * the importance of partnerships * future challenges

Pacific island countries face a tsunami threat that consists of a complex mix of tsunamis from local, regional and distant sources. Assessment of risk on these islands requires the ability to model tsunami inundation, and such modelling is complicated by the fact that they are often surrounded by shallow coral reef systems whose influence on tsunami propagation is poorly understood. These islands also suffer from a lack of both bathymetry and topography data of sufficient resolution to accurately model tsunami inundation. Geoscience Australia and the Pacific Islands Applied Geoscience Commission (SOPAC) have been developing a capacity for tsunami inundation modeling in support of risk assessment for Pacific islands that relies on remote sensing for nearshore bathymetric data coverage, including shallow reef platforms. This technique uses a physics-based modeling approach that estimates bathymetry from multispectral imagery, based on an optimisation driven per-pixel estimation of a set of environmental variables, including water column depth, from a semi-analytical expression of sub-surface remote sensing reflectance. Using this approach we have developed models for shallow bathymetry for off Nuku'alofa in Tongatapu and Gizo in the Solomon Islands, and merged these models with available swath bathymetry and global bathymetry data to produce bathymetry grids suitable for modelling tsunami inundation. We have attempted to validate these models against data for the 2006 Tonga (Mw=8.0) and 2007 Solomon Islands (MW=8.1) earthquakes, respectively.

The information within this document and associated DVD is intended to assist emergency managers in tsunami planning and preparation activities. The Attorney General's Department (AGD) has supported Geoscience Australia (GA) in developing a range of products to support the understanding of tsunami hazard through the Australian Tsunami Warning System Project. The work reported here is intended to further build the capacity of the Tasmanian State Government in developing inundation models for prioritised locations.

The Attorney General's Department (AGD) has supported Geoscience Australia (GA) to develop inundation models for one South Australia (SA) community with the view of building the tsunami planning and preparation capacity of the SA State Government. The community that was chosen was Victor Harbor, which also includes the townships of Port Elliot and Middleton. These locations were selected in collaboration with the SA State Emergency Service (SES), SA Department of Environment and Natural Resources (DENR) and the Australian Government based on the National Near Shore Tsunami Hazard Assessment [1] that highlighted tsunami amplification near Victor Harbor. Three tsunamigenic events were selected for modelling from the scenario database that was calculated as part of the national offshore probabilistic Probabilistic Tsunami Hazard Aassessment (PTHA) [2]. The events selected are hypothetical and are based on the current understanding of the tsunami hazard. Only earthquake sources are considered as these account for the majority of tsunami that have historically been observed in Australia. The suite of events includes three 'worst-case' or 1 in 10 000 year hazard event from three different source zones; the Puysegur Trench, Java Trench and South Sandwhich Islands Trench. These three source zones were identified from the PTHA to contribute significantly to the offshore tsunami hazard near Victor Harbor.

The tragic events of the Indian Ocean tsunami on 26 December 2004 highlighted the need for reliable and effective alert and response sysems for tsunami threat to Australian communities. Geoscience Australia has established collaborative partnerships with state and federal emergency management agencies to support better preparedness and to improve community awareness of tsunami risks.

Legacy product - no abstract available