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Contemporary crustal stress pattern of Australia

Thursday, July 23, 2020
1200 (AWST)
1300 (AWST)

Title: Contemporary crustal stress pattern of Australia

 

Summary:

The present-day stress field of Australia has been the subject of great interest in the three past decades because it shows a variable pattern for the orientation of maximum horizontal stress (SHmax) that is not parallel to absolute plate motion. Analysis of in-situ stress data across Australia (in >20 sedimentary basins) reveals four major trends for the orientation of SHmax including NE-SW in northern, northwestern and northeastern Australia, E-W in southern half of Western Australia and South Australia, ENE-WSW in most parts of eastern Australia and NW-SE in southeastern Australia. In addition, the results reveal significant rotation of stress within various sedimentary basins due to the presence of different geological structures, including basement structures, faults, fractures and lithological contrasts. Understanding and predicting local stress perturbations has major implications for determining the most productive fractures in petroleum and geothermal systems, and for modelling the propagation direction and vertical height growth of induced hydraulic fractures in unconventional reservoirs.

Biography of the presenter:

Dr Mojtaba Rajabi is an ARC DECRA Fellow at the School of Earth and Environmental Sciences, University of Queensland. He has over 12 years of extensive experience in crustal stress analysis, reservoir geomechanics, geomechanical-numerical modelling and petrophysics. He graduated with a Ph.D. in Earth Sciences from the University of Adelaide in 2017. Dr Rajabi has worked on the geomechanical analyses of >30 sedimentary basins from across the world including Australia, New Zealand, Middle East, Mozambique, Iceland and Western Mediterranean. Since 2012, Dr Rajabi has worked on the Australian and World Stress Map projects. He has received >15 international awards and prizes for his research including the ARC-DECRA Award, the Australian SEG Early Achievement Award, EAGE Louis Cagniard Award, and the International Lithosphere Program’s Flinn-Hart Award.

Ten years in the wild (Redux)

Tuesday, July 7, 2020
1200 (AEST)
1300 (AEST)

The ASEG welcome you to join us on ZOOM on Tuesday 7 July, 12pm (AEST) for a talk by David Annetts from CSIRO.

 

Ten years in the wild (Redux)

An updated and expanded version of the AEGC presentation providing background to a CSIRO project that was placed in the public domain in 2009.  The talk offers lessons and guidance for others who would walk a similar path.

The use of open-source codes has become pervasive over the past 20 years but such codes are uncommon in minerals exploration. The P223 series of programs researching forward and inverse modelling of electromagnetic data was supported by CSIRO and six AMIRA consortia over 27 years and produced, amongst others, the codes, Airbeo, LeroiAir and Marco. This project concluded in 2008 and, after a two-year embargo, the code base, consisting of computer programs modelling different approximations of the earth for ground and airborne prospecting systems, was released to the public. We discuss reasons why codes have not been more widely adopted, and examine the evolution of some of the codes in research, academia and in industry as a guide to parties who would embark on a similar route.

David Annetts has been with CSIRO since 2007. A forward-modeller by inclination, he has researched the application of frequency and time-domain electromagnetic prospecting methods to marine CSEM, CO2 sequestration, uranium and groundwater exploration, and maintains an active interest in CSIRO’s Bayesian Lithological Inversion initiative.  He is also the current ASEG President.

Register Now: https://us02web.zoom.us/webinar/register/WN_wRoI_iXERlmmAA-wtXjHLw

 

After registering, you will receive a confirmation email containing information about joining the webinar.

Mentoring through change, a perspective

Tuesday, July 14, 2020
1700 (AEST)
1800 (AEST)

Please join us on Tuesday 14th July,  5pm (AEST) for a talk by Marina Costelloe from Geoscience Australia hosted by FedEx.

 

Mentoring through change, a perspective

Building on her experience as an ASEG President, STEM ambassador, and senior manager with Geoscience Australia, this talk is aimed at geophysicists at any stage in their career and will cover our shared leadership challenges, what we need to do more of, and less of, where to go to for help and how you can make the most of new opportunities for your workplace, your teams and for you in your own leadership sphere. There will be lots of time for questions and discussions.

Biography:

Marina Costelloe is the Director of the Onshore Seismic and Magnetotelluric Section within the Mineral Systems Branch at Geoscience Australia. Marina has worked in areas as diverse as mineral exploration, groundwater, critical infrastructure, earthquakes, and data science and contributed to international nuclear monitoring and space weather over the past 25 years. In 2018, Marina took on the role of President of the Australian Society of Exploration Geophysics (ASEG). Marina represents the Geology and Geography Cluster on the board of Science and Technology Australia and represents Australia on the Society of Exploration Geophysics Pacific Regional Affairs Committee.

Register Now: https://us02web.zoom.us/webinar/register/WN_quT25XVVTLGxJNTyy3XE_Q

 

After registering, you will receive a confirmation email containing information about joining the webinar. Contact secretary@aseg.org.au if you have any questions.  

 

Please bring your own drinks and nibbles.

ASEG Webinar: Coupling Surface Evolution and Mantle Dynamics: two examples of the interplay of Tectonics,

Wednesday, June 17, 2020
1800 (AEST)
1900 (AEST)

Please join us on Wednesday 17th June,  6pm (AEST) for a talk by Claire Mallard from USYD.

 

Coupling Surface Evolution and Mantle Dynamics: two examples of the interplay of Tectonics, Eustasy and Surface Processes

Over deep time, mantle flow-induced dynamic topography as well as plate tectonic evolution drive deposition moderated by higher-frequency fluctuations in climate and sea level. The effects of deep mantle convection and lithospheric deformation impact all the segment of the source to sink systems at different wavelengths and over various scales which remains poorly quantified. Field observations and numerical investigations suggest that the long-term stratigraphic record along continental margins contains essential clues on the interactions between dynamic topography and surface processes. However, it remains challenging to isolate the fingerprints of dynamic topography, lithospheric deformation, eustatic variation and climate change in the geological record.

In the first part of the talk, I will show you how we use a new numerical simulation package that couples the open-source surface evolution code Badlands (https://badlands.readthedocs.io/en/latest/) with lithospheric-scale thermo-mechanical models (https://uwgeodynamics.readthedocs.io/en/latest/) for unravelling the effect of rift obliquity on the distribution of facies and the evolution of stratigraphic architecture in syn-rift deposits.

The second part will focus on the integration of mantle convection simulation results into Badlands to quantify the impact of different timings and wavelengths of dynamic topography migration on the surface. I will present an example of the last 40 Ma evolution of the South African landscape.

 

The results suggest that our source-to-sink numerical workflow can be used to explore, in a systematic way, the interplay between dynamic topography and surface processes and can provide insights into recognizing the geomorphic and stratigraphic signals of dynamic topography in the geological record.

Register Now: https://us02web.zoom.us/webinar/register/WN_lf3ScLqiRCyGYll3gLcUnA

 

After registering, you will receive a confirmation email containing information about joining the webinar. Contact secretary@aseg.org.au if you have any questions.  

 

Please bring your own drinks and nibbles.

ACT Tech night - Computations methods in Geophysics

Wednesday, July 15, 2020
1630 (AEST)
1730 (AEST)

Date: Wednesday 15 July

Presenter: Indrajit G. Roy (PhD)

A link to the Zoom webinar will be shared closer to the event date.

Title: Computations methods in Geophysics

Abstract:

Mathematical derivatives, since their birth within calculus in the last quarter of seventeenth century, have been occupying a most important place in almost every sphere of science.  They are fundamental to geophysical modelling and particularly potential field data analysis, from data presentation through to quantitative interpretation. But the challenges of robust and precise estimation of derivatives along with their implementation are many. This presentation will review some of those challenges, how to minimize errors and provide insight into many of their applications.

 

ASEG Webinar: Seismic Attribute Illumination of complex fault network North Slope, Alaska

Thursday, June 25, 2020
12:00 (AEST)
13:00 (AEST)

Please join us on Thursday 25th June, 12:00pm (AEST) for a talk by Sumit Verma from University of Texas of Permian Basin (UTPB).

 

Seismic Attribute Illumination of complex fault network North Slope, Alaska

The North Slope, Alaska has a complex fault system in the subsurface due to different episodes of tectonics. The most producing reservoirs are fault controlled. Our study area lies in the south of the well-known Prudhoe Bay and Kuparuk River oil fields. The Triassic-aged Shublik Shale, which is the most prominent source rock, has gone through three stages of extensional tectonic activities during the Jurassic, Cretaceous, and Eocene. To understand the complex fault system, we computed an ensemble of volumetric seismic attributes, including coherence, curvature and aberrancy, and studied them along the Shublik Shale surface. In this study, we have divided the structures into three types based on seismic signature, 1. significant fault throw on vertical seismic section, 2. insignificant fault throw but clearly visible flexure, 3. insignificant fault throw and very weak flexure. We observed type 1 faults on the vertical seismic section, and seismic attributes which trends in WNW direction, these faults have large lateral extent. The type 2 faults have similar orientation as type 1. The type 2 faults are clearly visible on the curvature and aberrancy attributes. Although, the type 3 structures have no visible throw on vertical seismic, but, it can be seen as two fault lineation (which are orthogonal each other) on curvature and aberrancy attributes. Based on our attribute analysis and regional geologic understanding, we believe that, the type 1 and type 2 fault sets are of Jurassic age, whereas the two faults of the type 3 were formed in Cretaceous and Eocene with an orientation of nearly east-west and north-south orientation. These type 1 faults display cross cutting, single-tip and double-tip abutting relations with the older west-north-west striking faults.

 

Biography:

Dr. Sumit Verma is an Assistant Professor of Geophysics at UTPB. Dr. Verma received his M.S. (2007) in Applied Geophysics from the Indian School of Mines - Dhanbad, and his Ph.D. (2015) in Geophysics from the University of Oklahoma. After earning his PhD, he worked for one year as a Postdoctoral Research Fellow at the University of Wyoming. Dr. Verma also worked with Reliance Industries Ltd. E&P for four years (2007-2011) as a development geoscientist. Dr. Verma’s research areas are Seismic Interpretation, Quantitative Interpretation and Reservoir Characterization. Dr. Verma is a deputy editor for the peer-reviewed scientific journal: Interpretation.

 

Register Now: https://us02web.zoom.us/webinar/register/WN_Myhly7WKS6uTu0wS9bldQw

 

After registering, you will receive a confirmation email containing information about joining the webinar. Contact secretary@aseg.org.au if you have any questions.  

 

Please bring your own drinks and nibbles.

ASEG Webinar: Probabilistic Seismic Full Waveform Inversion (FWI)

Thursday, June 11, 2020
1400 (AEST)
1500 (AEST)

Please join us on Thursday 11th June, 2:00pm (AEST) for a talk by Anandaroop Ray

 

Probabilistic Seismic Full Waveform Inversion (FWI)

 

Register Now: https://us02web.zoom.us/webinar/register/WN_MBfv_1tRSeuLMq-7PvKI_Q

 

After registering, you will receive a confirmation email containing information about joining the webinar. Contact secretary@aseg.org.au if you have any questions.  

 

Please bring your own drinks and nibbles.

 

Probabilistic Seismic Full Waveform Inversion (FWI)

Limited illumination, insufficient offset, noisy data and poor starting models can pose challenges for seismic full waveform inversion (FWI). Appropriately formulated Bayesian approaches can mitigate these problems by appealing to parsimony, i.e., low model dimension, and through rigorous quantification of prior knowledge. Given the flexibility of the Bayesian framework, the theory can include the inference of nuisance parameters such as the source wavelet and data noise. Given the tandem developments in statistical inference and HPC, sampling based approaches to FWI are able to provide a surprising amount of subsurface information. While the non-linearity of wave physics is indeed a significant obstacle for inversion algorithms, it is also the reason why inferences, should we reach the appropriate local minima (or posterior probability maxima), are so much more informative than for diffusive or potential field geophysics. Through a combination of synthetic and real data examples, this talk will attempt to encourage further research in this arena.

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.

 

ASEG Webinar - SA/NT Branch: Searching for the Beaumont Children and Other Adventures in Unmarked Grave Detection

Tuesday, June 2, 2020
1230 AEST
1330 AEST

Branch hosting the event: SA/NT

Title: Searching for the Beaumont Children and Other Adventures in Unmarked Grave Detection

Presenter: Dr Ian Moffat

Date: Tuesday 2nd June 12:30 pm AEST

 

Abstract:

The reliable detection of unmarked graves is one of the most important challenges faced by community groups, industry and law enforcement agencies. Burials are ubiquitous in the archaeological and forensic record however these features are challenging to locate with conventional techniques. Geophysical methods are often used for this purpose due to their non-invasive nature and rapid site coverage however graves remain a difficult target due to their subtle response and small size. This presentation reviews a number of grave detection projects, including the search for the Beaumont Children and mapping WWII graves from the Battle of Tarawa, to discuss current best practice in this field.

Bio:

Ian Moffat is an ARC DECRA Senior Research Fellow in Archaeological Science at Flinders University where he undertakes research in the application of earth science techniques in archaeology. He has previously held research positions at the University of Cambridge and the Institute for Mediterranean Studies. Ian holds a PhD from the ANU and a BA and BSc (Hons) from UQ. In addition to his academic career he has worked at Ecophyte Technologies, Precipice Training and Archaeometry Pty Ltd.

 

ASEG Webinar - VIC Branch: How remote is remote sensing from Geophysics?

Wednesday, May 27, 2020
1800 (AEST)
1900 (AEST)

The VIC Branch of the ASEG invite you to join us on ZOOM for the next talk in the ASEG Webinar Series.

 

Please join us on Wednesday 27th May, 6:00 pm (AEST) for a talk by Dr Rob Hewson, University of Twente, NL.

 

How remote is remote sensing from Geophysics?

 

The question of remote sensing’s place in the exploration tool kit has often raised questions, if not eye brows for many geologists / geophysicists. This talk provides a brief overview of the new and available satellite/airborne sensors and archived imagery, to add to this discussion – the advantages, caveats and relevance of it in the tool box. Examples include the AEGC2019 presentation of the multi-sensor and airborne geophysics case study over the Haib Cu porphyry deposit, Namibia.

 

Register Now: https://us02web.zoom.us/webinar/register/WN_tUhOokagSAK9h-HhK7m5Gw

 

After registering, you will receive a confirmation email containing information about joining the webinar.

 

 

Please bring your own drinks and nibbles.

 

Contact secretary@aseg.org.au if you have any questions. 

 

Rob has also requested that the below link be attached which will be discussed during the webinar.

https://2019.aegc.com.au/programdirectory/docs/224.pdf

ASEG Webinar: How regional geophysical data has reshaped tectonic analysis of the Australian continent

Tuesday, May 26, 2020
1800 (AEST)
1900 (AEST)

FedEx invite you to join us on ZOOM for the next talk in the ASEG Webinar Series.

 

Please join us on Tuesday 26th May, 6:00 pm (AEST) for a talk by Peter Betts from Monash University.

 

How regional geophysical data has reshaped tectonic analysis of the Australian continent

 

Regional aeromagnetic and gravity data is a powerful tool for tectonic analysis because it can be interpreted and modelled at different scales, and it is very effective at imaging different crustal levels.  The signal in the data can also be linked to geological features and processes, and importantly, it is amenable to structural analysis, which can be used to inform 3D geometry, kinematics, and overprinting relationships.  When combined with geological context the data can constrain tectonic settings and evolutions, and importantly provide context for mineral system analysis.  We use examples from the IOCG belts of Proterozoic Australia.  We present data from the Mount Woods Inlier in the northern Gawler Craton and interpret what is likely one of the oldest preserved metamorphic core complexes on Earth.  We then illustrate how tectonic analysis can be used to resolve complex geology of the Mount Painter Inlier in the northern Curnamona Province.

 

Register Now: https://us02web.zoom.us/webinar/register/WN_tqrwjkA0TqmCENkoO92R7A

 

After registering, you will receive a confirmation email containing information about joining the webinar.

 

 

Pete Betts is a Professor in the School of Earth, Atmosphere and Environment and is the Associate Dean of Graduate Research in the Faculty of Science.  His expertise is in structural analysis of regional aeromagnetic and gravity datasets, forward modelling of gravity and magnetic data, regional tectonic and geodynamic analysis, ancient and modern tectonic synthesis.  He has a diverse portfolio of research that includes the dynamics of congested subduction, ocean initiation processes in the Red Sea, tectonic evolution of the Australian Plate, mineral system analysis, New Zealand Tectonics and geophysics of volcanoes.  He has been awarded the Geological Society of Australia Bruce Hobbs and S.W Carey medals for his contributions to Australian tectonics.  He has extensive consulting experience with the Australian and international exploration community where he predominately delivers regional geological synthesis and high-resolution aeromagnetic interpretations to target mineral deposits and reduce exploration risk.

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