As part of AGSO's commitment to advancing exploration technology, the Petroleum and Marine Division has been conducting studies into the use of fluorescence signatures as a means of detecting, mapping and typing hydrocarbon seeps to their sources. AGSO's aim is to provide data that will allow sea surface hydrocarbon anomalies, detected during Airborne Laser Fluorosensor (ALF) surveys, to be correlated with oils and ultimately characterise the anomalies directly to their source. This report concludes the second stage of AGSO's `remote sensing' multi-client study and comprises ultra-violet fluorescence (UVF) `surface maps' of 60 open file western Australian oils. This report is a stand alone product, with supplementary geological, spectroscopic and geochemical information for the oil set described herein, being presented in Part 1 of this study (Edwards et al., 1998).

This is a joint product developed by GA and Skyring Environment Entetrprises. It is an animated CDROM developed specifically in Authoware software for state of the art visual presentation.

We investigate two intraplate earthquakes in a stable continental region of southwest Western Australia. Both small-magnitude events occur in the top »1 km of crust and their epicenters are located with an accuracy of »100 m (1¾) using satellite Interferometric Synthetic Aperture Radar (InSAR). For the Mw 4.7 Katanning earthquake (10 October 2007) the average slip magnitude is 42 cm, over a rupture area of »1 km2. This implies a high stress drop of 14-27 MPa and, even for this very shallow earthquake, has important implications for regional seismic hazard assessment. The earthquake rupture extends from a depth of around 640 m to the surface, making it a rarely observed intraplate, surface-rupturing event. Using InSAR observations we estimate the coseismic slip distribution of the shallow earthquake, such estimates being rarely available for small magnitude events. For the Mw 4.4 composite Kalannie earthquake sequence (21-22 September 2005) we use a long-term time series analysis technique to improve the measurement of the co-seismic signal, which is a maximum of 27 mm in the line-of-sight direction. Double difference seismic analysis shows some relocated cluster seismicity which corresponds in timing, location and source parameters to the InSAR-observed deformation. This earthquake is the smallest magnitude seismic event investigated using InSAR and demonstrates the capability of the technique to provide important constraints on small-magnitude coseismic events. The shallow depth of both these events adds weight to the suggestion that earthquakes associated with tectonic processes in this area of Western Australia often initiate in the upper 1 km of crust.

Soil mapping at the local- (paddock), to continental-scale, may be improved through remote hyperspectral imaging of surface mineralogy. This opportunity is demonstrated for the semiarid Tick Hill test site (20 km2) near Mount Isa in western Queensland, which is part of a larger Queensland government initiative involving the public delivery of 25,000 km2 of processed airborne hyperspectral mineral maps at 4.5 m pixel resolution to the mineral exploration industry. Some of the "soil" mineral maps for the Tick Hill area include the abundances and/or physicochemistries (chemical composition and crystal disorder) of dioctahedral clays (kaolin, illite-muscovite and Al smectite, both montmorillonite and beidellite), ferric/ferrous minerals (hematite/goethite, Fe2+-bearing silicates/carbonates) and hydrated silica (opal) as well as "soil" water (bound and unbound) and green and dry (cellulose/lignin) vegetation. Validation of these hyperspectral mineral products is based on field sampling and laboratory analyses (spectral reflectance, X-ray diffraction, scanning electron microscope and electron backscatter). The mineral maps show more detailed information regards the surface composition compared with the published soil and geology (1:100,000 scale) maps and airborne radiometric imagery (collected at 200 m line spacing). This mineral information can be used to improve the published mapping but also has the potential to provide quantitative information suitable for soil modeling/monitoring.

The datasets measure the Total Suspended Materials (TSM) concentrations of ocean surface waters. They are derived products from MODIS (aqua) images using NASA's SeaDAS image processing software. The extent of the datasets covers the entire Australian EEZ and surrounding waters (including the southern ocean). The spatial resolution of the datasets is 0.01 dd. The datasets contain 36 monthly TSM layers between 2009 and 2011. The unit of the datasets is g/m3.

The datasets measure the K490 parameter (Downwelling diffuse attenuation coefficient at 490 nm, a turbidity parameter) of Australian oceans. They are derived products from MODIS (aqua) images using NASA's SeaDAS image processing software. The extent of the datasets covers the entire Australian EEZ and surrounding waters (including the southern ocean). The spatial resolution of the datasets is 0.01 dd. The datasets contain 36 monthly k490 layers between 2009 and 2011. The unit of the datasets is 1/m.

The datasets measure the Sea Surface Temperature (SST) of Australian oceans. They are derived products from MODIS (aqua) images using NASA's SeaDAS image processing software. The extent of the datasets covers the entire Australian EEZ and surrounding waters (including the southern ocean). The spatial resolution of the datasets is 0.01 dd. The datasets contain 126 monthly SST layers between 2002 and 2012.

Geoscience Australia Flyer prepared for LOCATE14.

Airborne laser fluorosensor (ALF) data was acquired by BP in Australia between 1990 and 1991 and originally processed by BP immediately after acquisition. The data was reprocessed by Signalworks Pty Ltd in 2000 and 2001 with significant differences in the number of fluors picked and oil seepage distributions interpreted. A comparison of the data processing and interpretation techniques shows similar methods used by both companies. The main difference with the Signalworks interpretation is that a larger number of lower confidence fluors are used to determine the seepage distributions. Low signal to noise ratio (S/N) in the MkII ALF data used is the main cause of data analysis difficulties and differences between interpretations. This problem was greatly reduced in the MkIII system developed later which results in more consistent interpretations between companies. Another problem with ALF surveys covering very large areas is the pattern of background fluorescence / Raman area ratios (F/R) that can affect the pattern of picked fluors. Both BP and Signalworks use an averaging technique to determine the background F/R levels over the survey. The BP analysis has usually resulted in very few picked fluors and little information about seepage patterns. The Signalworks analysis has attempted to pick sufficient fluors to define seepage patterns but is affected by the low S/N and background F/R patterns.

The regional assessment of hydrocarbon seepage is built around a combination of Radarsat and ERS Synthetic Aperture Radar (SAR) data, acquired during 1998 and 1999, as part of a collaborative project between AGSO - Geoscience Australia, Nigel Press & Associates, Radarsat International and AUSLIG (specifically the Australian Centre for Remote Sensing). In total, 55 Radarsat Wide 1 Beam Mode scenes and 1 ERS scene from the Great Australian Bight (GAB) region were analysed. The data were integrated with regional geological information, and other hydrocarbon migration/seepage indicators such as reprocessed and reinterpreted legacy Airborne Laser Fluorosensor (ALF) data, to provide an assessment of the possible charge characteristics of the region. The results of the study suggest that active, though areally restricted, liquid hydrocarbon seepage is occurring within the Bight Basin. The majority of seepage slicks occur along the outer margin of the major depocentre, the Ceduna Sub-basin, in areas where significant Late Tertiary to Recent faulting extends to the seafloor. Very little evidence of seepage was observed on the SAR data above the main depocentre, which is an area of minimal Late Tertiary to Recent faulting. Reprocessed ALF data reveal three main areas with relatively dense fluors. Although they are not directly coincident with locations of seepage interpreted from SAR data, their distribution support the pattern of preferred leakage along the basin margins. Integration of regional geological models with the results of this study suggests that structural features related to active tectonism have focused laterally migrating hydrocarbons to produce active seepage at specific locations in the basin. Where these features are absent, seepage may be passive and/or be governed by long distance migration to points of seal failure. Together with oil and gas shows in exploration wells, observations from this study provide further evidence that liquid hydrocarbons have been generated in the Great Australian Bight.