In 2009, Geoscience Australia (GA) entered into a partnership with the Australia-Indonesia Facility for Disaster Reduction (AIFDR) and the Centre for Volcanogy and Geohazard Mitigation (CVGHM), the Government of Indonesia centre responsible for assessing, analysing and monitoring volcanic hazards in Indonesia. A series of collaborative activities were undertaken between 2009 and 2013 focussed on the development and implementation of a volcanic ash modelling capability in Indonesia. Activity 1 (2009-2010) focused on evaluating a range of existing volcanic ash dispersal models, developing a set of criteria needed for volcanic ash hazard modelling in Indonesia, identifying a model which satisfied the majority of these criteria (FALL3D) and obtaining recommendations from CVGHM staff on how FALL3D could be adapted and simplified for use by their agency. Activity 2 (2010-2012) involved validating FALL3D against historical eruptions in Indonesia in order to assess the accuracy and degree of uncertainty in the simulations. FALL3D was then modified for users with little or no background in computational modelling and limited computing resources. A scripted user interface was developed (PF3D) which modifies the modelling procedure of FALL3D to simplify its use without compromising the core functionality of the model. PF3D was implemented as part of a case study on four volcanoes located in West Java during the development of a methodology for probabilistic hazard assessment. Activity 3 (2012-2013) focused on expanding the capability of CVGHM to include near-real time volcanic ash forecasting during an event. A methodology for implementing near-real time forecasts of volcanic ash dispersal using PF3D prior to and during an eruption was developed and implemented at two volcanoes in North Sulawesi. The collaborative nature of this partnership continues today through ongoing maintenance and improvements made to the PF3D tool, sharing of modelled data/information and the provision of technical assistance both during and between volcanic crises.

Extended abstract for the 21st International Geophysical Conference and Exhibition, Sydney, 2010

Frontier sedimentary basins are characterised by deep water, difficult geology (basalts and salt), remoteness and harsh met-ocean conditions. These characteristics present significant challenges to marine surveying, which means that frontier basins tend to be underexplored. With continuing interest in exploration for energy resources in frontier regions, many frontier basins around the world have been the focus of increasingly-sophisticated geophysical studies that integrate a range of methodologies. Underexplored frontier basins around Australia's continental margin have received increased attention during the last decade, largely as a result of government-funded programs of precompetitive data acquisition and analysis. The geophysical component of this work includes: first-pass depth-to-basement estimation using spectral techniques applied to magnetic data; enhancement of gravity and magnetic images to aid the identification of basin depocentres and to facilitate onshore-offshore geological interpretation of basement structure; multi-scale edge-detection applied to gravity and magnetic data to aid the interpretation of basement structure; 3D forward and stochastic inverse modelling of gravity data to guide seismic interpretation of sediment thickness and basement structure; using supercomputers for high-resolution, regional-scale 3D inverse modelling of magnetic and gravity data to constrain the physical properties of the crust. Despite the additional insight offered by this work, efforts to understand frontier basins are not without challenges, one of the most fundamental of which is to ensure that non-specialists are using data in the right ways. The other main challenge in Australian frontier basins arises from a lack of constraints on crustal structure. This leads to significant ambiguity when using gravity data to infer sediment thickness or to understand the nature of basement. This ambiguity could be vastly reduced through the acquisition of seismic refraction data that focuses on imaging crustal structure. Further opportunities exist in using alternative methods for automated depth-to-basement estimation, incorporating process in modelling, and in applying 3D forward and inverse gravity and magnetic modelling to other Australian frontier basins.

The Queen Charlotte Fault (QCF) off western Canada is the northern equivalent to the San Andreas Pacific - America boundary. Geomorphology and surface processes associated with the QCF system have been revealed in unprecedented detail by recent seabed mapping surveys carried out by the Canadian Hydrographic Service and the Geological Survey of Canada.

Knowledge of the degree of damage to residential structures expected from severe wind is used to study the benefits from adaptation strategies developed in response to expected changes in wind severity due to climate change, inform the insurance industry and provide emergency services with estimates of expected damage. A series of heuristic wind vulnerability curves for Australian residential structures has been developed for the National Wind Exposure project. In order to provide rigor to the heuristic curves and to enable quantitative assessment to be made of adaptation strategies, work has commenced by Geoscience Australia in collaboration with James Cook University and JDH Consulting to produce a simulation tool to quantitatively assess damage to buildings from severe wind. The simulation tool accounts for variability in wind profile, shielding, structural strength, pressure coefficients, building orientation, component self weights, debris damage and water ingress via a Monte Carlo approach. The software takes a component-based approach to modelling building vulnerability. It is based on the premise that overall building damage is strongly related to the failure of key components (i.e. connections). If these failures can be ascertained, and associated damage from debris and water penetration reliably estimated, scenarios of complete building damage can be assessed. This approach has been developed with varying degrees of rigor by researchers around the world and is best practice for the insurance industry. This project involves the integration of existing Australian work and the development of additional key components required to complete the process.

Recent field observations have identified the widespread occurrence of fluid seepage through the eastern Mediterranean Sea floor in association with mud volcanism or along deep faults. Gas hydrates and methane seeps are frequently found in cold seep areas and were anticipated targets of the MEDINAUT/MEDINETH initiatives. The study presented herein has utilized a multi-disciplinary approach incorporating observations and sampling of visually selected sites by the manned submersible Nautile and by ship-based sediment coring and geophysical surveys. The study focuses on the biogeochemical and ecological processes and conditions related to methane seepage, especially the anaerobic oxidation of methane (AOM), associated with ascending fluids on Kazan mud volcano in the eastern Mediterranean. Sampling of adjacent box cores for studies on the microbiology, biomarkers, pore water and solid phase geochemistry allowed us to integrate different biogeochemical data within a spatially highly heterogeneous system. Geophysical results clearly indicate the spatial heterogeneity of mud volcano environments. Results from pore water geochemistry and modeling efforts indicate that the rate of AOM is 6 mol m-2 year-1, which is lower than at active seep sites associated with conditions of focused flow, but greater than diffusion-dominated sites. Furthermore, under the non-focused flow conditions at Kazan mud volcano advective flow velocities are of the order of a few centimeters per year and gas hydrate formation is predicted to occur at a sediment depth of about 2 m and below. The methane flux through these sediments supports a large and diverse community of micro- and macrobiota, as demonstrated by carbon isotopic measurements on bulk organic matter, authigenic carbonates, specific biomarker compounds, and macrofaunal tissues...

This paper discusses two of the key inputs used to produce the draft National Earthquake Hazard Map for Australia: 1) the earthquake catalogue and 2) the ground-motion prediction equations (GMPEs). The composite catalogue used draws upon information from three key catalogues for Australian and regional earthquakes; a catalogue of Australian earthquakes provided by Gary Gibson, Geoscience Australia's QUAKES, and the International Seismological Centre. A complex logic is then applied to select preferred location and magnitude of earthquakes depending on spatial and temporal criteria. Because disparate local magnitude equations were used through time, we performed first order magnitude corrections to standardise magnitude estimates to be consistent with the attenuation of contemporary local magnitude ML formulae. Whilst most earthquake magnitudes do not change significantly, our methodology can result in reductions of up to one local magnitude unit in certain cases. Subsequent ML-MW (moment magnitude) corrections were applied. The catalogue was declustered using a magnitude dependent spatio-temporal filter. Previously identified blasts were removed and a time-of-day filter was developed to further deblast the catalogue.

Geoscience Australia is currently conducting a study under the National CO2 Infrastructure Plan (NCIP) to assess suitability of the Vlaming Sub-basin for CO2 storage. It involves characterisation of the potential seal, the Early Cretaceous South Perth Shale (SPS), by integrating seismic and well log interpretation into a sequence stratigraphic framework. The SPS, conventionally described as a regional seal deposited during a post-rift thermal subsidence phase, consists of a series of prograding units deposited in a deltaic to shallow marine setting. Mapping of the SPS has revealed differences in the geometries of progradational sequences between the northern and southern areas, related to the type and distance to the sediment source as well as the seafloor morphology. In the northern area, deltaic progradation and aggradation occurred over a flat topography between the two uplifted blocks. The succession is composed of prograding sequences commonly exhibiting sigmoidal to oblique geometries, prograding from the north-east to south-west. In the southern area the topography is more complex due to the presence of several paleotopographic highs associated with pre-existing structures. These sequences are sigmoidal to oblique in cross section. They were deposited in fan shaped lobes, successively infilling paleotopographic lows. Direction of the progradation is from southwest to northeast. The thickness of the SPS varies from 200 m between topographic highs to 700 m in the lows. Sedimentary facies are interpreted to vary from sandy delta front to muddy slope and prodelta deposits. These findings will be used in a 3D geological model for assessing CO2 storage potential.

Terrain affects optical satellite images through both irradiance and BRDF effects. It results in the slopes facing toward the sun receiving enhanced solar irradiance and appearing brighter compared to those facing away from the sun. For anisotropic surfaces, the radiance received at the satellite sensor from a sloping surface is also affected by surface BRDF which varies with combinations of surface landcover types, sun, and satellite as well as topographic geometry. Consequently, to obtain comparable surface reflectance from satellite images covering mountainous areas, it is necessary to process the images to reduce or remove the topographic effect so that the images can be used for different purposes. The most common method of normalising for the topographic effect is by using a Digital Surface Model (DSM). However, the accuracy of the correction depends on the accuracy, scale and spatial resolution of DSM data as well as the co-registration between the DSM and satellite images. A physically based BRDF and atmospheric correction model in conjunction with the 1-second SRTM derived DSM product were used to conduct the analysis. The results show that artefacts in the DSM data can cause significant local errors in the correction. For some areas, false shadow and over corrected surface reflectance factors have been observed. In other areas, the algorithm is unable to detect shadow or retrieve an accurate surface reflectance factor. The accuracy of co-registration between satellite images and DSM data is important for the topographic correction. A mis-registration error of one or two pixels can lead to large error in the gully and ridge areas. Therefore, accurate registration for both satellite images and DSM data is necessary to ensure the accuracy of the correction. Using low resolution DSM data to correct high resolution satellite images can fail to correct some significant terrain effects.

The Perth Basin formed as part of an obliquely-oriented extensional rift system on Australia's southwestern margin during the Paleozoic to Mesozoic breakup of eastern Gondwana. The Houtman Sub-basin is situated in the offshore portion of the northern Perth Basin, located about 200 km northwest of Perth. It is an elongate, northwest-southeast trending depocentre containing up to 14 km of Early Triassic to Late Jurassic sedimentary strata. A detailed sequence stratigraphic study has been undertaken on the three wells in the Houtman Sub-basin: Gun Island 1, Houtman 1 and Charon 1. The purpose of this study was to investigate facies variations between the wells to gain a better understanding of potential source, reservoir and seal distribution and to assist regional palaeogeographic reconstructions of the Perth Basin. The study focussed on the Early-Late Jurassic succession comprising the Cattamarra Coal Measures, Cadda Formation and Yarragadee Formation. Wireline log character, cuttings, sidewall core and conventional core lithologies and palynological data were used to identify facies and paleoenvironments. Palynology for all wells has been reviewed, including new data collected by Geoscience Australia for Gun Island 1 and Charon 1. Facies stacking patterns were used to define systems tracts and subsequently ten third-order depositional sequences. Collectively these sequences define a larger scale, second-order (supersequence) transgressive-regressive cycle. The Cattamarra Sequence Set forms a regional transgression which culminates in an extensive marine maximum flooding event within the Cadda Sequence Set. These sequence sets are followed by the regressive highstand Yarragadee Sequence Set. The third-order sequences characterised in this study overprint this supersequence and control the local distribution of facies. The combined influence of these third- and second-order sequences on facies distribution has significant implications for the distribution of potential reservoirs and seals, particularly in the northern Houtman Sub-basin where well and seismic data are relatively sparse.