b'AEGC 2021Short abstractsa range of mud weights between 8.35ppg and 10ppg areof New South Wales (GSNSW) has now incorporated the required to avoid breakout, depending on the approach takennew data into an updated suite of magnetic imagery with for Shmin estimation. much greater anomaly resolution than previous versions. The statewide imagery is based on more than 60 regional 116: Seismic network modelling and design in angovernment surveys flown at 200400 m line-spacings. interactive web-based environment Adding approximately 250 private company surveys flown at 50200 m line-spacings has improved the image quality and Dr Pavel Golodoniuc 1, Dr Januka Attanayake2, Mr Abrahamhas allowed the data to be gridded at a smaller cell size (25 m Jones2 and Mr Samuel Bradley1 vs 50 m) to prevent under-sampling of complex magnetic signatures.1 CSIRO2 University of Melbourne The project started with the quality assurance of more than 800 company geophysical surveys acquired in NSW. An Detecting and locating earthquakes relies on seismic eventsalgorithm was derived allowing a quantitative assessment of being recorded by a number of deployed seismometers. Toeach survey, which applied a weighted score to aspects such detect earthquakes effectively and accurately, seismologistsas line-spacing, flight height, sampling interval and survey must design and install a network of seismometers that cansize. A baseline score was calculated for the previous statewide capture small seismic events in the sub-surface. products based on the regional government surveys. It A major challenge when deploying an array of seismometersbecame the cut-off for the company data, excluding all surveys (seismic array) is predicting the smallest earthquake thatfalling below that mark.could be detected and located by that network. VaryingThe merged Total Magnetic Intensity (TMI) grid was used the spacing and number of seismometers dramaticallyas the building block to create a series of enhancements. affects network sensitivity and location precision and isReduction to the Pole (RTP), First and Second Vertical very important when researchers are investigating small- Derivative (1VD & 2VD), and tilt angle filters were applied magnitude local earthquakes. For cost reasons, it is importantto the data, which were then re-projected into a suite of to optimise network design before deploying seismometers inprojections relevant for NSW. The grids were used to create the field. In doing so, seismologists must accurately accountthe high-resolution magnetic imagery available on the for parameters such as station locations, site-specific noiseGSNSW portalMinViewdelivering best-available image levels, earthquake source parameters, seismic velocity andresolution statewide, especially in regions with company attenuation in the wave propagation medium, signal-to- data. This allows for more comprehensive delineation of noise ratios, and the minimum number of stations required tomagnetic features to aid geological interpretation and compute high-quality locations. geophysical exploration.AuScope AVRE Engage Programme team has worked with researchers from the seismology team at the University of118: Structural controls on late Cambrian Melbourne to better understand their solution for optimisingmineralisation in the Stavely Arcseismic array design to date: an analytical method called SENSI that has been developed by Tramelli etal. (2013)Dr Robert Holm 1, Mr Chris Cairns2, Ms Jennifer Murphy2, Mr to design seismic networks, including the GipNet arrayHamish Forgan2, Dr Michael Agnew2 and Mr Ian Stockton1deployed to monitor seismicity in the Gippsland region in Victoria, Australia. The underlying physics and mechanics1 CSA Globalof the method are straightforward, and when applied2 Stavely Mineralssensibly, can be used as a basis for the design of seismicThe middle-late Cambrian Stavely Arc forms the eastern networks anywhere in the world. Our engineers have built anboundary of the Delamerian Orogen in Victoria, Australia. A application leveraging a previously developed Geophysicalpulse of mineralised magmatism at ca. 500 Ma coincided with Processing Toolkit (GPT) as an application platform andthe collision of VanDieland and related deformation. Porphyry harnessed the scalability of a Cloud environment providedintrusion during this event has previously been inferred, from by the EASI Hub, which minimised the overall developmenttectonic reconstructions, to coincide with a change from D1a time. The GPT application platform provided the groundworktranspression to D1b transtension, with intrusions having for a web-based application interface and enabled interactiveexploited transtensional structures. The outcropping area of visualisations to facilitate human-computer interaction andthe Stavely Arc is a small proportion of the total terrane, and experimentation. informative outcrops and data are sparse, providing limited supporting evidence to date.117: A beautiful sunset (clause): enhancing statewideThis work presents new insights into the structural geology of geophysics with high resolution company data the Stavely Arc during porphyry emplacement. A bottom-up 1 approach is informed by structural observations and exploration Dr Sam Matthews activity from the Thursdays Gossan-Cayley Lode Project of 1 Geological Survey of New South Wales Stavely Minerals Limited. This data-orientated approach utilises measured structures and assay results from exploration drilling, Most New South Wales (NSW) airborne geophysical dataas opposed to a top-down approach interpreted from the acquired by industry before 2016 became open file on 1regional geodynamics.June 2021 under the NSW Governments Mining Regulation Amendment (2016), which introduced a 5 year sunset clauseAn evaluation of mineralised versus non-mineralised structures on confidential company reports. The Geological Surveywas used as a proxy for active versus inactive structures, 81 PREVIEW AUGUST 2021'