b'Geophysics in the surveysNewsdata, surface observations, well data,the geometry of the top of basementinterpretation of basement structure magnetic data and seismic reflectioninterface, which plays a key role inusing 3D inversion modelling of interpretations. petroleum prospectivity. Specifically,airborne gravity data. Victorian Pre-existing seismic reflectioninversion results suggest that the PortlandGas Program Technical Report 63. interpretations of the basin were usedTrough in the southwestern region ofGeological Survey of Victoria, as a starting model. However, highthe onshore Otway Basin is significantlyDepartment of Jobs, Precincts and amplitude gravity signatures, most likelydeeper than previously thought. Regions, Melbourne, Victoria.attributed to the diversity of geology inPowell, W.D., Nourollah, M.H., Tait, the basement, needed to be modelledReferences A.M., Saitta, A.J., Kirk, R., Woollard, first. Previous models of Victorias crustalK. & Bubrzycki, M., 2020. Regional architecture were used with the additionCarter, S., van Galder, C., Mohammed- 3D geological framework model, of new surfaces to build structures withinNour, J., Reeve-Fowkes, M., Cowey,Gippsland Basin, Victoria. Victorian the basement. This was followed byD., McLean, M.A., Haydon, S.J.,Gas Program Technical Report 20. refinements to the interface betweenLane, R.J., & Zengerer, M., 2019. FullGeological Survey of Victoria.the sedimentary basin and top of theSpectrum FALCON airborne gravityRomine, K., Vizy, J., Nelson, G., Lee, J.D., basement. Forward and inversionand aeromagnetic survey, OtwayBaird, J. & Boyd, M., 2020. Regional 3D modelling results suggest that significantBasin, Victoria. Victorian Gas Programgeological framework model, Otway gravity anomalies are also caused by theTechnical Report 6. Department ofBasin, Victoria. Victorian Gas Program shape of the Moho. The Moho depth wasJobs, Precincts and Regions. Technical Report 35. Geological Survey therefore incorporated into the model toDunne, J. & Boyd, M., 2020. Regionalof Victoria. Department of Jobs, account for its influence on the gravityvelocity modelling and depthPrecincts and Regions. Melbourne, signature. conversion, Otway Basin. VictorianVictoria.Gas Program Technical Report 39. This study has improved theGeological Survey of Victoria. Suzanne Haydon understanding of the basement structuresMcLean, M.A., Pears, G.A., Boyd, M.Geological Survey of Victoria below the Otway Basin. It has also refined& Cayley, R.A., 2021. QuantitativeSuzanne.Haydon@ecodev.vic.gov.auFree subscription to Preview online Non-members of the ASEG can now subscribe to Preview online via the ASEG website. Subscription is free. Just go to https://www.aseg.org.au/publications/PVCurrent to sign up. You will receive an email alert as soon a new issue of Preview becomes available. Stay informed and keep up-to-date by subscribing now!!NB: ASEG Members dont need to subscribe as they automatically receive an email alert whenever a new issue of Preview is published.29 PREVIEW AUGUST 2021'