Why do cliffs and overhangs drop rocks? Cliffs are formed and wear away by erosion. Water and wind blast the rock with solid particles, waves pound the cliffs, and water dissolves minerals in the rocks. As the cliffs wear away, they form overhangs that weaken, break and fall suddenly. Rocks can also fall off cliffs if water or tree roots enter cracks behind the cliff face. On 27 September 1996, people were sheltering under an overhang in a limestone cliff near Gracetown, Western Australia. The overhang and part of the cliff behind collapsed, and about 2500 tonne of rock and sand fell. Nine people were killed and three others injured. The collapse was partly attributed to the rock absorbing water and becoming heavier. Remember, it is natural for rocks to fall off cliffs!

This is a short movie is an alternate showing of bathymetric fly through data and underwater seafloor video captured by PMD staff during the Southwest Marine Margin survey 2009.

SHRIMP U-Pb zircon ages and Sm-Nd data are presented from a variety of samples from volcanic and sedimentary rocks from northeastern Eyre Peninsula, South Australia.

The impacts of climate change, including sea level rise and the increased frequency of storm surge events, will adversely affect infrastructure in a significant number of Australian coastal communities. In order to quantify this risk and develop suitable adaptation strategies, the Department of Climate Change and Energy Efficiency (DCCEE) commissioned the National Coastal Vulnerability Assessment (NCVA). With contributions from Geoscience Australia (GA) and the University of Tasmania, this first-pass national assessment has identified the extent and value of infrastructure that is potentially vulnerable to impacts of climate change. In addition, the NCVA examined the changes in exposure under a range of future population scenarios. The NCVA was underpinned by a number of fundamental national scale datasets; a mid-resolution digital elevation model (DEM) used to model a series of sea level rise projections incorporating 1 in 100 year storm-tide estimates where available; the 'Smartline' (nationa; coastal geomorphology dataset) identified coastal landforms that are potentially unstable and may recede with the influence of rising sea level. The inundation outputs were then overlain with GA's National Exposure Information System to quantify the number and value of infrastructure elements (including residential and commercial buildings, roads and rail) potentially vulnerable to a range of sea-level rise and recession estimates for the year 2100.

Abstract prepared for submission to ABLOS for Conference in October 2010

This project was conducted by Geoscience Australia in collaboration with the Water Science Branch of the Department of Water, Western Australia, to acquire baseline information supporting the condition assessment for Hardy Inlet. The project contributes to the Estuarine Resource Condition Indicators project funded by the Strategic Reserve of the National Action Plan for Salinity and Water Quality / National Heritage Trust and forms part of the Resource Condition Monitoring endorsed under the State (Western Australia) Natural Resource Management framework. Two surveys were undertaken in Hardy Inlet in September 2007 and April 2008 with the aim to develop an understanding of the historical environmental changes and current nutrient and sediment conditions for the purpose of developing sediment indicators to characterise estuary condition.

Map showing Australia's Maritime Jurisdiction in Bass Strait. One of the 27 constituent maps of the "Australia's Maritime Jurisdiction Map Series" (GeoCat 71789). Depicting Australia's extended continental shelf, approved by the Commission on the Limits of the Continental Shelf in April 2008, and various maritime zones. Background bathymetric image is derived from a combination of the 2009 9 arc second bathymetric and topographic grid by GA and a grid by Smith and Sandwell, 1997. A0 sized portrait format .pdf downloadable from the web.

Describes the global earthquake model (GEM) and how GA will work with GEM

The Arrowie Basin in South Australia represents the last phase of sedimentation in the Neoproterozoic to Cambrian Adelaide Rift System. As part of the Onshore Energy Security Program funded by the Australian Government, Geoscience Australia, in conjunction with PIRSA, acquired a ~60 km long deep seismic line (08GA-A1) in 2008 across the Arrowie Basin, immediately to the west of the central Flinders Ranges. The basin is of interest for petroleum exploration, because about 15 km to the south of the seismic line, the Wilkatana wells, drilled in the 1950s, encountered non-commercial bituminous hydrocarbons in the Cambrian succession. In 2009, Torrens Energy acquired a ~40 km long seismic line (09TE-01) at Parachilna, about 90 km to the north of the GA line as part of their geothermal exploration program. In the vicinity of these seismic lines, the Arrowie Basin forms part of the essentially undeformed Stuart Shelf (in the west) and the Torrens Hinge Zone (a zone of faulting and folding in the east). The Torrens Hinge Zone occurs immediately to the west of the highly folded component of the Adelaide Rift System in the Flinders Ranges.

In this review we aim to synthesise physical and biological information on the Lord Howe Rise (LHR) region to describe its biogeography at a regional scale (100s of kilometres) and assess this in a national and global context. The LHR region is large (1.95 million km2), spans tropical and cool temperate latitudes (18.4oS to 40.3oS), and is topographically complex being formed of large expanses of soft sediment basins and plateaus (i.e. subdued bathymetric features), with scattered seamounts, guyots, knolls, and pinnacles (i.e. raised bathymetric features). Physical factors can vary between these two broad feature types, particularly regarding depth and substrate, although no clear relationship was detected between sediment texture and geomorphic features across the survey area. Biological data from two recent surveys (TAN0713 and NORFANZ) show differences in assemblages and species distribution between raised and subdued bathymetric features and suggest that biological communities are indeed influenced by substrate as well as depth-related variables, with some taxa such as demersal fish showing latitudinal gradients. There are only limited spatially-replicated studies and no time-series data available for most of the LHR region, but paleo-environmental processes and examples from other regions provide some indication of migration, speciation, and endemism in the LHR region.