Faults of the Lapstone Structural Complex (LSC) underlie 100 km, and perhaps as much as 160 km, of the eastern range front of the Blue Mountains, west of Sydney, Australia. More than a dozen major faults and monoclinal flexures have been mapped along its extent. Debate continues as to the age of formation of the ~400 m or more of relief relating to the LSC, with estimates ranging from Palaeozoic to Pliocene. The results of an investigation of Mountain Lagoon, a small basin bound on its eastern side by the Kurrajong Fault in the central part of the LSC, favour a predominantly pre-Neogene origin. Drilling on the eastern margin of the lagoon identified 15 m of fluvial, colluvial and lacustrine sediments, overlying shale bedrock. The sediments are trapped behind a sandstone barrier corresponding to the Kurrajong Fault. Dating of pollen grains preserved in sediments at the base of this sediment column suggest that the fault-angle depression began trapping sediment in the Early to Middle Miocene. Strongly heated Permo-Triassic gymnosperm pollen in the same strata provides circumstantial evidence that sediment accumulation post-dates the ca. 18.8 Ma emplacement of the nearby Green Scrub basalt. Our data indicate that only 15 m of the 130 m of throw across the Kurrajong Fault has occurred during the Neogene suggesting a predominantly erosional exhumation origin for current relief at the eastern edge of the Blue Mountains plateau. Sedimentation since the Late Pleistocene appears to have been controlled largely by climatic processes, with tectonism exerting little or no influence.

A geological investigation was carried out by the writer. The aim was to check the previous mapping of the geology, and if necessary, to assist the Magnetician in locating a suitable site for magnetic observations. Some aspects of geomorphology, and the reconnaissance survey work carried out are discussed in this report.

During the summer of 1947, an expedition was despatched to Heard Island with the object of landing a party to spend about twelve months there. Geological work was undertaken by the writer. The results of this work are recorded in this report. These results include observations on the geomorphology of the island, and a description of the xenolithic ejectamenta collected from the tuffs of Rogers Head and Rogers Head Peninsula.

Surveying of nearshore areas in the Vestfold Hills using high resolution multibeam swath bathymetry provides both a detailed digital bathymetric model and information on sediment acoustic backscatter. Combined with underwater video transects and sediment sampling, these data can be used to identify and map geomorphic units. Six geomorphic units identified in the survey region include: Rocky outcrops, sediment-floored basins, pediments, steep-sided valleys, scarps and sheltered embayments. In addition to geomorphic units, the data reveal sedimentary structures that provide insights into sediment transport and erosion in the area. Ice keel pits and scours are common while seafloor channels, scour depressions and sand ribbons indicate transport and deposition by wind-driven currents and oceanographic circulation. Gullies and sediment lobes on steep slopes indicate mass movement of sediment. The sheltered embayments preserve a mantle of boulder sand probably deposited by cold-based glaciers. Automated techniques utilizing the bathymetric grid and backscatter to map landforms are useful in defining reproducible boundaries between geomorphic units but cannot easily be adapted to accurately classify the variations in sea floor texture and structure imaged by these data.

Probabilistic seismic hazard analyses in Australia rely fundamentally on the assumption that earthquakes recorded in the past are indicative of where earthquakes will occur in the future. No attempt has yet been made to assess the potential contribution that data from active fault sources might make to the modelling process, despite successful incorporation of such data into United States and New Zealand hazard maps in recent years. In this paper we review the limited history of paleoseismological investigation in Australia and discuss the potential contribution of active fault source data towards improving our understanding of intraplate seismicity. The availability and suitability of Australian active fault source data for incorporation into future probabilistic hazard models is assessed, and appropriate methodologies for achieving this proposed.

For the first time, the distribution of seabed geomorphic features has been systematically mapped over the Australian margin. Each of 21 feature types was identified using a new, 250 m spatial resolution bathymetry model and supporting literature. The total area mapped was >8.9 million km2 and included the seabed surrounding the Australian mainland and island territories of Christmas, Cocos (Keeling), Macquarie and Norfolk Islands. Of this total, the shelf is >1.9 million km2 (21.92%), the slope >4.0 million km2 (44.80%), and the abyssal plain/deep ocean floor >2.8 million km2 (32.20%). The rise covers 97,070 km2 or 1.08% of the margin. A total of 6,702 individual geomorphic features were mapped on the Australian margin. Plateaus have the largest surface area and cover 1.49 million km2 or 16.54%, followed by basins (714,000 km2; 7.98%), and terraces (577,700 km2; 6.44%), with the remaining 14 types each making up <5%. Reefs, which total 4,172 individual features (47,900 km2; 0.54%), are the most numerous type of geomorphic feature, principally due to the large number of individual coral reefs of the Great Barrier Reef. The geomorphology of the margin is most complex where marginal plateaus, terraces, trench/troughs and submarine canyons are present. Comparison with global seabed geomorphology indicates that the Australian margin is relatively under-represented in shelf, rise and abyssal plain/deep ocean floor area and over-represented in slope area, a pattern that reflects the mainland being bounded on three sides by passive continent-ocean rifted margins and associated numerous subsided marginal plateaus. Significantly, marginal plateaus on the Australian margin cover 20% of the total world area of marginal plateaus. The Australian margin can be divided into 10 geomorphic regions by quantifying regional differences in diagnostic features that can be used to infer broad-scale seabed habitats. The present study has application for the future management of Australia's ocean resources.

This record contains the raw Ground Penetrating Radar (GPR) data and scanned field notes collected on fieldwork at Old Bar and Boomerang Beaches, NSW for the Bushfire and Natural Hazards CRC Project, Resilience to Clustered Disaster Events on the Coast - Storm Surge. The data was collected from 3 - 5 March 2015 using a MALA ProEx GPR system with 250 MHz shielded and 100 MHz unshielded antennaes. The aim of the field work was to identify and define a minimum thickness for the beach and dune systems, and where possible depth to any identifiable competent substrate (e.g. bedrock) or pre-Holocene surface which may influence the erosion potential of incident wave energy. Surface elevation data was co-acquired and used to topographically correct the GPR profiles.

This record contains the processed Ground Penetrating Radar (GPR) data (.segy), field notes, and shapefiles collected on fieldwork at Old Bar and Boomerang Beaches, NSW for the Bushfire and Natural Hazards CRC Project, Resilience to Clustered Disaster Events on the Coast - Storm Surge. The data was collected from 3 - 5 March 2015 using a MALA ProEx GPR system with 250 MHz shielded and 100 MHz unshielded antennaes. The aim of the field work was to identify and define a minimum thickness for the beach and dune systems, and where possible depth to any identifiable competent substrate (e.g. bedrock) or pre-Holocene surface which may influence the erosion potential of incident wave energy. Surface elevation data was co-acquired and used to topographically correct the GPR profiles. This dataset is published with the permission of the CEO, Geoscience Australia.

Abstract: The Collaborative East Antarctic Marine Census (CEAMARC) surveys to the Terre Adélie and George V shelf and margin highlight the requirement for a revised high resolution depth model that can be used as a spatial tool for improving physical models of the region. We have combined available shiptrack and multibeam bathymetry, coastline and land topographic data to develop a new high-resolution depth model, called GVdem. GVdem spans an area 138°E to 148°E longitude and 63°S to 69°S latitude, with a choice of three ESRI grids with cell pixel sizes: 15 arcsec, 9 arcsec and 3.6 arcsec. The revised depth model is an improvement over previously available regional-scale grids, and highlights seabed physiographic detail not previously observed for this part of East Antarctica. In particular, the extent and complexity of the inner-shelf depressions are revealed and their relationship with large shelf basins and adjacent flat-topped banks.

Continental Australia is characterised overall by relatively high levels of seismic activity in comparison with intracratonic areas worldwide. However, the link between earthquake events and earthquake-related geomorphology in Australia remains poorly understood for all except the largest events, because landscape impact unambiguously attributable to seismic activity is typically difficult to recognise. In this context, we describe several unusual fracture systems of possible tectonic origin that transect granite pavements in the Archaean eastern Pilbara Craton of Western Australia. Occurring at four localities (Gallery Hill, North Shaw, Mulgandinnah Hill and Muccan) separated by up to 150 km, the fracture systems typically range up to 100 m in length and 20 m in width, locally offset pavement surfaces by up to 15 cm vertically, and expose uniformly fresh-looking rock. At one locality (Muccan), the fractures directly crosscut two generations of aboriginal petroglyphs etched into the pavement surface, which suggests that fracture formation occurred relatively recently, and probably quite rapidly. All four localities are characterised by extensional structures (tension fractures and dilated joints) striking 020?040?, and three preserve compressional structures (steeply-dipping reverse faults at Gallery Hill and North Shaw, A-tent crestal fractures at Mulgandinnah Hill) trending 100?135?. These strongly correlated alignments militate against an origin controlled purely by weathering-related phenomena, and the observed pattern is compatible with the formation of all documented fracture systems within a single East Pilbara-wide stress field, dominated by pure shear and characterised by NE?SW to NNE?SSW directed maximum horizontal compression. This orientation is consistent with that derived via spatial averaging of the stress orientation data available from northwestern Australia. The results are preliminary, but have exciting implications for: (1) inexpensive field-based determination of regional stress orientation, and (2) probabilistic seismic hazard assessment and the identification of earthquake-prone regions using granitic landforms.