Understanding the long-term periodicity of extreme intensity tropical cyclones is important for determining their role as ecological disturbance mechanisms1-5; for predicting present and future community vulnerability and economic loss6; and for assessing whether changes in their variability are a function of anthropogenically induced climate change7. Our ability to accurately make these assessments has been limited by the short (<100yrs) instrumented cyclone record. We overcame this problem by determining the intensity of prehistoric tropical cyclones that deposited ridges of detrital coral and shell above highest tide over the past 5,000 years and eroded terraces into coarse-grained alluvial fans that form sea-cliffs. These features occur along 1500 km of the Great Barrier Reef (GBR) and also the Gulf of Carpentaria, Australia. They were formed by storms with recurrence intervals of 2-3 centuries8-11 and our results show that the cyclones responsible were of extreme intensity (<920 hPa central pressure). This revised frequency of super-cyclones is an order of magnitude higher than the previously estimated once every several millennia and is sufficiently high to suggest the character of rainforests and coral reef communities is shaped by these events.

The impact of natural hazards on Australian communities can be devastating. After such events, the devastation is commonly measured in terms of costs to property, businesses and infrastructure. The challenge is to better understand our communities so that a more comprehensive management of total risk can be taken. Such a task requires a multi-disciplinary approach, and Geoscience Australia is collaborating with the Bureau of Meteorology, Emergency Management Australia, Local Government Agencies and Universities to develop a better understanding of how natural hazards affect communities.

Severe Tropical Cyclone Larry crossed the far north Queensland coast near Etty Bay around 7 a.m. on 20 March, 2006. It then tracked west-northwest and passed directly over the town of Innisfail (Figure 1). Within 48 hours, teams from Geoscience Australia were on the ground to begin a program of assessing building and crop damage. This continued for 3 weeks. The initial analysis of data collected is presented below.

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 evolution of the Australian Landslide Database (ALD) was driven by the need for a nationally consistent system of data collection in order to develop a sound knowledge base on landslide hazard and inform landslide mitigation strategies. The use of 'networked service-oriented interoperability' to connect disparate landslide inventories into a single 'virtual' national database, promotes a culture of working together and sharing data to ensure landslide information is easily accessible and discoverable to those who need it. The ALD overcomes obstacles which traditionally hamper efforts of exchanging data, such as variations in data format and levels of detail to establish the foundation for a very powerful and extensible coordinated landslide resource in Australia. Such a resource synthesises the capabilities of specific single-purpose inventories and provides a suitable basis for further investment in data collection and analysis. The approach is centred upon a 'common data model' that addresses aspects of landslides captured by different agencies. The methodology brings four distinct components together: a landslide application schema; a landslide domain model; web service implementations and a user interface. The successful implementation of these components is demonstrated in connecting three physically separate and unique landslide event databases via the web. This allows users to simultaneously search and query remote databases in real time and view data consistently. The ALD is now a joint initiative across local, state and national levels with all levels contributing to a national picture. At implementation, this approach resulted in an immediate 70 per cent increase in the total number of landslide events reported nationally etc....

Defining a neotectonic fault in the intraplate context is relatively straightforward - the fault must have hosted displacement in the current crusta stress regime. Defining an active fault is far more problematic, depending upon the recurrence of the fault (and nearby faults) and the return period being considered for hazard purposes. This article discusses the term "active" and provides some examples of faults from eastern Australia for emphasis.

Abstract: Severe wind is one of the major natural hazards affecting Australia. The main wind hazards contributing to economic loss in Australia are tropical cyclones, thunderstorms and mid-latitude storms. Geoscience Australia's Risk and Impact Analysis Group (RIAG) has developed mathematical models to study a number of natural hazards including wind hazard. In this paper, we describe a model to study 'combined' gust wind hazard produced by thunderstorm and mid-latitude or synoptic storms. The model is aimed at applications in regions where these two wind types dominate the hazard spectrum across all return periods (most of the Australian continent apart from the coastal region stretching north from about 27 degrees south). Each of these severe wind types is generated by different physical phenomena and poses a different hazard to the built environment. For these reasons, it is necessary to model them separately. The return period calculated for each wind type is then combined probabilistically to produce the combined gust wind return period, the indicator used to quantify severe wind hazard. The combined wind hazard model utilises climate-simulated wind speeds and hence it allows wind analysts to assess the impact of climate change on future wind hazard. It aims to study severe wind hazard in the non-cyclonic regions of Australia (region 'A', as defined in the Australian/NZ Wind Loading Standard, AS/NZS 1170.2:2002) which are dominated by thunderstorm and synoptic winds.

The Mount Lofty and Flinders Ranges of South Australia are bound on the east and the west by reverse faults that thrust Proterozoic and/or Cambrian basement rocks over Quaternary sediment. These faults range from a few tens to almost one hundred kilometres in length and tend to be spaced significantly less than a fault length apart. In the few instances where the thickness of overthrust sediment can be estimated, total neotectonic throws are in the order of 100-200 m. Slip rates on individual faults range from 0.02-0.17 mm/a, with one unconfirmed estimate as high as 0.7 mm/a. Taking into account the intermittent nature of faulting in Australia, it has been suggested that 30-50% of the present-day elevation of the Flinders and Mount Lofty Ranges relative to adjacent piedmonts has developed in the last 5 Ma. Uplifted last interglacial shorelines (ca. 120 ka) along the southern coastline of the Mount Lofty Ranges indicate that deformation is ongoing. Palaeoseismological investigations provide important insight into the characteristics of the large earthquakes responsible for deformation events. Single event displacements of 1.8 m have been measured on the Williamstown-Meadows Fault and the Alma Fault, with the former relating to a surface rupture length of a least 25 km. Further to the south in Adelaide's eastern suburbs, a 5 km section of scarp, potentially relating to a single event slip on the Eden-Burnside Fault, is preserved in ca. 120 ka sediments. Where the Eden-Burnside Fault meets the coast at Port Stanvac 20 kilometres south, the last interglacial shoreline is uplifted by 2 m relative to its expected position. At Normanville, on the uplifted side of the Willunga Fault, the last interglacial shoreline is over 10 m above its expected position, implying perhaps five or more surface rupturing events in the last ca. 120 ka on this >50 km long fault. On the eastern range front, a very large single event displacement of 7 m is inferred on the 54 km long Milendella Fault, and the 79 km long Encounter Fault displaces last interglacial shorelines by up to 11 m. There is abundant evidence for large surface-breaking earthquakes on many faults within 100 km of the Adelaide CBD. Slip rates are low by plate margin standards, implying a low rate of recurrence for M7+ events on individual faults (perhaps 10,000 years or more). However, a proximal moderate-sized event or even a large event at distance has the potential to cause significant damage to Adelaide, particularly given its construction types and local site conditions.

This report comprises three parts, authored as indicated: Part I: Geoscience Australia. Cechet B. and Sanabria A. Part II: Bureau of Meteorology and JDH Consulting. Kepert J. and Holmes J. Part III: Cyclone Testing Station, James Cook University. Ginger J. and Henderson D

Community risk within the local government authority is investigated for: tropical cyclones and storm tide, east coast lows, thunderstorms, tropical cyclones and severe wind, flood, earthquake, landslide, heat wave and bushfire. Magnitude/returne period scenarios are developed and impact on communities investigated.