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ASEG Webinar: Preconditioned Compressive Sensing for Wavefield Reconstruction

Thursday, September 2, 2021
1300 AEST
1400 AEST

Title: Preconditioned Compressive Sensing for Wavefield Reconstruction, Applications to tomography, Helmholtz-Hodge decomposition and Distributed Acoustic Sensing

Presenter: Jack Muir

Date/Time: Sep 2, 2021 1300 (AEST)

Registration: https://us02web.zoom.us/webinar/register/WN_Sr40IBw9SmiEnyMh5dOY4w

 

Abstract: The proliferation of large seismic arrays have opened many new avenues of geophysical research; however most techniques still fundamentally treat regional and global scale seismic networks as a collection of individual time series rather than as a single unified data product. Wavefield reconstruction allows us to turn a collection of individual records into a single structured form that treats the seismic wavefield as a coherent 3D or 4D entity. We propose a split processing scheme based on a wavelet transform in time and Laplacian preconditioned curvelet based compressive sensing in space to create a sparse representation of the continuous seismic wavefield with smooth second order derivatives. Using this representation, we will illustrate three applications that require accurate access to the full wavefield including spatial gradients - 

Bio: Jack Muir

Jack is a 6th year graduate student in geophysics at the California Institute of Technology Seismological Laboratory (Caltech Seismolab) –- he will take up a Marie Skłodowska-Curie Fellowship at the Oxford University Department of Earth Sciences in late 2021 / early 2022, and is currently a visiting researcher at the Australian National University. He is passionate about inverse problems — some of the projects he is working on now are: imaging the Earth from near surface to the core; improving data captured at seismic arrays; and answering difficult questions about historical data sets.

Tech talk - Application of Multi-Scale Magnetotelluric Data to Mineral Exploration: An Example from the East Tennant Region, Northern Australia

Thursday, August 12, 2021
1100 AEST
1200 AEST

Title: Application of Multi-Scale Magnetotelluric Data to Mineral Exploration: An Example from the East Tennant Region, Northern Australia

Presenter: Wenping Jiang, Geoscience Australia

When: 12th August,2021 at 11am AEST

Registation: https://us02web.zoom.us/webinar/register/WN_gKKtAD8MRwaRCNUp-DNwNA

Abstract: 

The footprint of a mineral system is potentially detectable at a range of scales and lithospheric depths. Magnetotellurics is one of few techniques that can provide multi-scale datasets to image and understand mineral systems. We have used long-period data from the Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) as a first-order reconnaissance survey to resolve large-scale lithospheric architecture for mapping areas of mineral potential in northern Australia. The 3D resistivity model reveals a broad conductivity anomaly in the lower crust and upper mantle to the east of Tennant Creek, representing a potential fertile source region. Results from a higher-resolution infill magnetotelluric survey reveal a favourable crustal architecture linking the lower, fertile source regions with potential depositional sites in the upper crust. This observation strongly suggests that the deep-penetrating major faults potentially acted as pathways for transporting metalliferous fluids to the upper crust where they could form mineral deposits. This result and its integration with other geophysical and geochronological datasets suggest high prospectivity for major mineral deposits in the vicinity of these major faults. In addition to these insights, interpretation of high-frequency magnetotelluric data helps to characterise cover and assist with selecting targets for stratigraphic drilling which, in turn, can validate the models and improve our understanding of basement geology, cover sequences and mineral potential.

This study demonstrates that integration of geophysical data from multi-scale surveys is an effective approach to scale reduction during mineral exploration in covered terranes.

Biography: Dr Wenping Jiang joined Geoscience Australia in 2012 after completing a PhD degree from the University of Sydney. Since Feb 2016, she has worked as a senior geophysicist in the Mineral Systems Branch, delivering precompetitive data and information to improve the understanding of mineral resource prospectivity. Her professional focus is mainly on Magnetotelluric data processing, modelling and interpretation.  

 

Managing Through (constant) Change And Uncertainty - The Key Dilemmas Facing Resources Industry Personnel

Tuesday, June 8, 2021
1600
1700

Title: Managing Through (constant) Change And Uncertainty -  The Key Dilemmas Facing Resources Industry Personnel

Presenter: Michelle Henderson

Date: Tuesday  8th June

Time: 16:00 AEST  

Location: Joint Zoom virtual + physical presentation at Geoscience Australia

Registration: https://us02web.zoom.us/webinar/register/WN_yNHpLyXNTOOXe5Qx4FsGSA

Abstract:

The cyclical nature of the resources industry creates very specific challenges across investment through to people management.  Faced with constant ‘instability’, often supply-limited expertise and the uncertainty over discovery, how do we hold on to our people, maintain their enthusiasm and continue to lead success?

As a professional coach across government and scientific agencies, Michelle brings extensive experience to the ‘problem’ and solution.  Her empathetic and pragmatic approach empowers professionals to not only manage change, but to enthusiastically grasp the opportunities it brings. 

Bio:

Michelle Henderson is a professional consultant and coach. She has been consulting to government and scientific agencies for the last six years. Her specialties include executive leadership, change and working with governments.

As a consultant Michelle combines her passion for leadership and innovation. She works with senior leaders to help them manage their teams, and themselves, in constantly changing environments. Her empathetic and pragmatic approach empowers professionals to not only manage change, but to actively seek opportunities to make positive change happen.

Prior to consulting, Michelle worked for 23 years at executive and senior executive levels in the areas of industry, innovation and science policy. Michelle has a deep understanding of Australia’s innovation system and the important role science discovery, research and commercialisation play in knowledge and wealth creation for Australia.

Michelle has postgraduate qualifications in Management (industry strategy) and vocational qualifications in training and development.  She is a level 1 accredited coach.

Shallow mantle convection beneath West Africa and source to sink at continental margins: A novel approach to reservoir prediction in offshore deep-water settings

Wednesday, April 21, 2021
1730 AEST
1900 AEST

Title: Shallow mantle convection beneath West Africa and source to sink at continental margins: A novel approach to reservoir prediction in offshore deep-water settings

Presenter: Dr Bhavik Harish Lodhia (UNSW)

Abstract:

Deep-water settings are prevalent in many of the world’s frontier basins. To better focus exploration spend in today’s challenging environment and predict reservoirs, a novel approach to close the loop between onshore denudation and offshore sediment deposition is required. Sedimentary flux measurements, regional subsidence patterns, tomographic models and simple isostatic calculations are combined to constrain the history of offshore solid sedimentary flux and sub-plate support of the Mauritanian Basin. We combine seismic reflection and well data along the West African margin with shear wave tomography and the uplift and magmatic history of the Cape Verde Rise to constrain thermal, spatial and temporal scales of upper mantle convection. Predictions of solid sedimentary flux to the Mauritanian Basin calculated by inversion of continental drainage are compared to observations in the Chinguetti field of the Mauritanian Basin.

Bio: Bhavik moved to Australia from the United Kingdom earlier this year and is currently a Postdoctoral Fellow in Energy Technology and Geophysics at UNSW. Bhavik graduated with a PhD in Geology and Geophysics at Imperial College London in 2019 and completed a masters/bachelors degree in Earth Sciences at St. Anne's College, University of Oxford in 2014. His work has focused on basin dynamics, geodynamics, sediment source to sink and petroleum systems modelling.

Register: https://us02web.zoom.us/webinar/register/WN_-_AXVmqGT5GGGUrJw-VODA

Attend in-person

Time:                    5:30 for 6pm start

Address:              Level 2, Club York (99 York St, Sydney. Room 'York 2')

Meeting registration:      https://www.surveymonkey.com/r/2V6JM9F by Sunday 18th April - due to COVID restrictions we require a registration for in-person meetings. If you have trouble registering please email nswsecretary@aseg.org.au 

Learning to learn about the earth, using Bayesian inference

Tuesday, April 13, 2021
1215 ACST
1315 ACST

Title: Learning to learn about the earth, using Bayesian inference

Presenter: Anandaroop Ray (Geoscience Australia)

Abstract: To understand earth processes, geoscientists infer subsurface earth properties such as electromagnetic resistivity or seismic velocity from surface observations such as magnetotelluric data or seismograms. These properties are used to populate an earth model vector, and the spatial variation of properties sheds light on the underlying earth structure and phenomena, from groundwater aquifers to plate tectonics. I will show that in order to make accurate inferences about earth properties, inferences can first be made about the underlying length scales of these properties. From a mathematical point of view, the length scales can be conveniently thought of as “properties” of earth properties. This can be treated in an “infer to infer” paradigm analogous to the “learning to learn” paradigm which is now commonplace in the machine learning literature. A non-stationary trans-dimensional Gaussian Process (TDGP) is used to parameterise earth properties, and a multi-channel stationary TDGP is used to parameterise the length scales. Using non-stationary kernels, i.e., kernels with spatially variable length scales, earth models with sharp discontinuities can also be represented within this framework. As GPs are multi-dimensional interpolators, the same theory and computer code can be used to solve geophysical problems in 1D, 2D and 3D. This is demonstrated through a combination of 1D and 2D non-linear regression examples and a controlled source electromagnetic field example.

Biography: Anandaroop Ray (“Anand”) started his career as a non-seismic geophysicist with Shell Exploration and Production in 2007. In 2010 he joined the PhD programme in marine electromagnetics at the Scripps Institution of Oceanography in San Diego, California. In 2014 he completed his thesis focusing on uncertainty estimation in electromagnetic inversion for marine hydrocarbon exploration. From 2012-19, he worked for Chevron R&D on various problems – controlled source electromagnetics (CSEM), seismic full waveform inversion (FWI), reservoir properties from seismic (RPFS), airborne electromagnetics (AEM), statistical hydrocarbon exploration lookback analyses, and the role of machine learning in geophysics. The question most asked through his work is “how credibly can we interpret our inversion model(s),” the answering of which often requires the use of high-performance computing (HPC) techniques. He currently co-advises a PhD student at Columbia University on Bayesian geophysical inversion and has been active in convening and organizing the Uncertainty in Geophysical Inversion session at the American Geophysical Union’s Fall Meeting. In March 2019 he joined the Minerals, Energy and Groundwater Division at Geoscience Australia, where he continues to work on inverse uncertainty, model representation and geostatistics.

Register: https://us02web.zoom.us/webinar/register/WN_j_B7TWtMQvOSxy9zTLj5Iw

The thrill of the chase: Finding (and funding) 100 iconic rocks for the National Rock Garden

Wednesday, March 31, 2021
1830
1930

You are invited to join online with GSA  -- 31 March 2021 – 6.30pm

 

Speaker: Brad Pillans, Chair of the National Rock Garden Steering Committee

Topic: The thrill of the chase: Finding (and funding) 100 iconic rocks for the National Rock Garden

Zoom link:  click here to watch

Abstract: When the National Rock Garden was officially launched in 2010 at the Australian Earth Sciences Convention in Canberra, it seemed a straightforward task to bring in a bunch of rocks from all around the country and tell the story of Australian geology. Are we there yet? Not quite, but the thrill of the chase remains as we build our national collection of 100 or more iconic rocks. In this presentation, Brad will reveal some of the great rocks we already have and some that we don’t have (but would like to have).

DISC 2020-2021: AUSTRALIA/VIRTUAL- Survey Design and Seismic Acquisition for Land, Marine, and In-between in Light of New Technology and Techniques by Dave Monk

Wednesday, August 11, 2021
1000 AEST
1700 AEST

Survey Design and Seismic Acquisition for Land, Marine, and In-between in Light of New Technology and Techniques

Registration: SEG DISC registration

ASEG members get the member price of $250US, and registration comes with free copy of the e-book.

Day 1 – August 10th

Start time: 8:00am – 12:00pm PERTH time

Day 2 – August 11th

Start time: 8:00am – 12:00pm PERTH time

Description

Seismic surveys are subject to many different design criteria, but often the parameters are established based on an outdated view of how data can be acquired, and how it will be processed. This course is designed to highlight what is possible using modern methods, and how they impact seismic survey design.

Survey designs are subject to a limited set of operational and geophysical considerations. What frequencies do we require (in the source), and what will or can we detect? What geometry will be utilized, and what record length will be recorded?

However, new techniques and processing methods require that we understand and answer a new and different set of questions:

  • Are classic survey geometries outdated? What geometry is optimum given almost limitless availability of channels, and how are these best deployed if they are not constrained to be connected together?
  • How do you QC data from a system that doesn’t permit real time views of data?
  • How do compressive sensing methodologies fit into classical geometry requirements, and can these significantly impact how data is acquired and processed? Is random “optimum” and is optimum unique?
  • Do offset and sampling requirements change if processing will utilize FWI and/or least squares migration?
  • Can very low frequencies be generated, detected and used for improved inversion?
  • How should simultaneous sources be utilized, and can subsequent data be separated from the continuous records that will be required if this technique is used? If two sources are better than one, are four better than two?
  • What should we expect of seismic data five or ten years from now?

This course is designed to cover some of the fundamentals of survey design, but will highlight the changes in technology that we have seen in the past five years, and those that are likely to develop in the next five years with a view to allowing seismic surveys to be designed and acquired to optimize technology efficiencies and interpretation requirements in light of new technology.

Goals

This course will not describe specific survey designs for particular geologic objectives, but after attending this course, the participant should:

  • Understand the basic geophysical requirements of a seismic survey, based on geologic objectives
  • Have a much-improved knowledge of the differences between classic survey design, and what is required for modern high-end processing techniques including FWI 
  • Understand the concepts of simultaneous sources, compressive sensing, node acquisition, and broadband data, and see how these fit into survey design techniques
  • Understand that there is a relationship between acquisition parameters and seismic image quality
  • Understand how the basic requirements tied to modern acquisition and processing ideas can fundamentally change the data that is presented to an interpreter, and why final data volumes can look significantly different from legacy data

Who should attend?

All those interested in seismic surveys should attend. Geophysicists involved in acquisition may discover new techniques and concepts which with they are unfamiliar. Geophysicists involved in processing seismic data will better understand the shortcomings of the data that they are given to process, and better understand what techniques will, and will not, work for a particular survey. The interpreter may better understand the difference between modern seismic volumes presented for interpretation, and the legacy data that he is accustomed to interpreting. For those directly involved in survey design, the concepts will open up the potential for acquiring better images of the subsurface more efficiently, and at less cost.

The course does not require extensive mathematical knowledge or background. Concepts will be explained in a way that the layman or manager can understand. Students will be able to follow and understand the course from the basics to the level of asking knowledgeable questions of those actually involved in seismic acquisition and processing.

DISC 2020-2021: AUSTRALIA/VIRTUAL- Survey Design and Seismic Acquisition for Land, Marine, and In-between in Light of New Technology and Techniques by Dave Monk

Tuesday, August 10, 2021
1000 AEST
1700 AEST

Survey Design and Seismic Acquisition for Land, Marine, and In-between in Light of New Technology and Techniques

Registration: SEG DISC registration

ASEG members get the member price of $250US, and registration comes with free copy of the e-book.

Day 1 – August 10th

Start time: 8:00am – 12:00pm PERTH time

Day 2 – August 11th

Start time: 8:00am – 12:00pm PERTH time

Description

Seismic surveys are subject to many different design criteria, but often the parameters are established based on an outdated view of how data can be acquired, and how it will be processed. This course is designed to highlight what is possible using modern methods, and how they impact seismic survey design.

Survey designs are subject to a limited set of operational and geophysical considerations. What frequencies do we require (in the source), and what will or can we detect? What geometry will be utilized, and what record length will be recorded?

However, new techniques and processing methods require that we understand and answer a new and different set of questions:

  • Are classic survey geometries outdated? What geometry is optimum given almost limitless availability of channels, and how are these best deployed if they are not constrained to be connected together?
  • How do you QC data from a system that doesn’t permit real time views of data?
  • How do compressive sensing methodologies fit into classical geometry requirements, and can these significantly impact how data is acquired and processed? Is random “optimum” and is optimum unique?
  • Do offset and sampling requirements change if processing will utilize FWI and/or least squares migration?
  • Can very low frequencies be generated, detected and used for improved inversion?
  • How should simultaneous sources be utilized, and can subsequent data be separated from the continuous records that will be required if this technique is used? If two sources are better than one, are four better than two?
  • What should we expect of seismic data five or ten years from now?

This course is designed to cover some of the fundamentals of survey design, but will highlight the changes in technology that we have seen in the past five years, and those that are likely to develop in the next five years with a view to allowing seismic surveys to be designed and acquired to optimize technology efficiencies and interpretation requirements in light of new technology.

Goals

This course will not describe specific survey designs for particular geologic objectives, but after attending this course, the participant should:

  • Understand the basic geophysical requirements of a seismic survey, based on geologic objectives
  • Have a much-improved knowledge of the differences between classic survey design, and what is required for modern high-end processing techniques including FWI 
  • Understand the concepts of simultaneous sources, compressive sensing, node acquisition, and broadband data, and see how these fit into survey design techniques
  • Understand that there is a relationship between acquisition parameters and seismic image quality
  • Understand how the basic requirements tied to modern acquisition and processing ideas can fundamentally change the data that is presented to an interpreter, and why final data volumes can look significantly different from legacy data

Who should attend?

All those interested in seismic surveys should attend. Geophysicists involved in acquisition may discover new techniques and concepts which with they are unfamiliar. Geophysicists involved in processing seismic data will better understand the shortcomings of the data that they are given to process, and better understand what techniques will, and will not, work for a particular survey. The interpreter may better understand the difference between modern seismic volumes presented for interpretation, and the legacy data that he is accustomed to interpreting. For those directly involved in survey design, the concepts will open up the potential for acquiring better images of the subsurface more efficiently, and at less cost.

The course does not require extensive mathematical knowledge or background. Concepts will be explained in a way that the layman or manager can understand. Students will be able to follow and understand the course from the basics to the level of asking knowledgeable questions of those actually involved in seismic acquisition and processing.

A personal reflection on applied geophysics to the understanding of Australia’s geology and mineral potential

Tuesday, March 30, 2021
1730 AEST
1830 AEST

Date: 30th March 2021

Time: 5:30 - 6:30pm AEDT

Register: https://us02web.zoom.us/webinar/register/WN_J6zK4TXCTbCI1PxCI4uF9g

 

Richard retired from Geoscience Australia after more than a 30 year career of developing new geological understanding to open up provinces for exploration investment. Applied geophysics played a key component throughout his career, and this seminar will be a personal reflection on the key ‘geophysical-aha’ moments that have changed his understanding of a region’s geology and, through this new knowledge, Australia’s mineral potential.

The 30-year story begins in the field as a young geologist using geophysics to map Cape York, Pilbara and Yilgarn and seismic transects across a number of Proterozoic orogens, through the UNCOVER formulation to the lead designer of the Exploring for the Future programme.
 

An explanation for the distribution of Broken Hill style mineralization invoking dense rift-related igneous intrusions.

Wednesday, March 17, 2021
1800 AEST
1900 AEST

Title:    An explanation for the distribution of Broken Hill style mineralization invoking dense rift-related igneous intrusions.

Presenter: Peter Gunn (MSc, PhD)
Day and Date of Event:    Wednesday 17th March 2021
Start and finish times:6:00 pm to 7:00 pm AEST

ABSTRACT
This talk is a revised version of an invited keynote presentation made at a Broken Hill Symposium in 2015.
 
The talk will suggest explanations for:
 
-                      the gravity field of the Broken Hill area
-                      the distribution and origin of the Ag-Pb-Zn mineralisation
-                      the distribution and origin of the Cu mineralisation
-                      the magnetic field of the Broken Hill area
-                      the original structure of the Broken Hill area
-                      the present structure of the Broken Hill area
-                      the topography of the Broken Hill area
-                      and - gives guidelines for exploring for Broken Hill type deposits.
 
Various workers have suggested that the Broken Hill area originated as a rift that was subsequently metamorphosed and intensively deformed. The presenter agrees with this idea and, based on his experiences with many well studied rifts elsewhere in the world, largely in the context of hydrocarbon exploration, identifies subtleties that do not appear to have been appreciated as applying to the Broken Hill rift.

Registration link: https://tas.currinda.com/register/event/2198

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