November 2015 Technical Talk

BCGS Technical Talk – November 19, 2015

Speaker: Willem de Beer, Principal, Golder Associates

Title: Automatic microseismic data processing using open source algorithms

Date/Time: Thursday, November 19, 2015 @ 4:30 pm

Location: Room 451, 409 Granville St (UK Building at Granville and Hastings), Vancouver


Over the last five years we have compiled a more or less coherent collection of scripts, a toolbox we call μQuake (microQuake) which enables us to efficiently, accurately and automatically, process seismic data. We believe that the field of “mine seismology” would benefit from having standardized, rigorously peer-reviewed tools. If these tools are open source, it reduces the “friction” slowing innovation considerably, as they can quickly be adapted and disseminated by and among mines, researchers and developers. In this talk we will study the performance of an open source library of microseismic data processing techniques based on programs routinely used by the earthquake community and released under permissive open source licenses, permitting event detection and association, P- and S-wave arrival time picking, event location in arbitrarily complex 3D velocity structures, source parameter characterization and advanced analysis.  We show the ability of the system to automatically process a data set collected in 2004 at Northparkes Mines E26 Lift 2 and compare the results to high quality manual processing, showing that the results are of similar if not better quality.

About the Authors:

Willem de Beer is a Principal of Golder Associates and a mathematical physicist with an innovation bug and a passion for applying esoteric concepts in mathematics and physics to practical problems. However, all analysis is critically dependent on data integrity, quantity and density, and therefore he learnt to design and implement industrially robust monitoring systems to deliver continuous and consistent data streams. He has  been back-analyzing and thinking about the rock mass response to mining over the last 17 years, using a variety of techniques from stock-in-trade statistical tools to sophisticated inversion and clustering methods. The one constant, though, in all the studies, is that it always starts with validating the data and ends with robust review by his rock mechanical engineering colleagues. He is a proponent of “design-as-you-mine” using real-time, online geotechnical and geophysical data streams and he designs systems to enable this. He has worked in South Africa, Australia, New Zealand, South America and North America.

Jean-Philippe Mercier is co-owner of Advanced GeoScience Imaging Solutions (AGSIS) and until recently was the Golder lead seismologist. He currently focuses primarily on mine seismology in the context of deep and high stress mining. Jean-Philippe’s main interest consists in developing processing techniques and monitoring approaches to exploit the untapped potential of seismological analysis in extracting information on the spatial and temporal response of the rock mass to mining. Dr Mercier earned a Ph.D. from UBC in crustal seismology and has co-authored multiple papers published in peer-reviewed journal and conference proceedings. He is the principal force behind, and developer of, the techniques presented today.

BCGS EM Workshop 2015 – Registration Now Open!

The BCGS Executive is pleased to announce that registration is now open for the fall 2015 EM Workshop.

When: Friday October 16, 2015

Where: BCIT Downtown Campus (555 Seymour St. Vancouver, BC)

Time: 8:00 am – 4:45 pm (PST)

Cost: Regular $120 / Student $60

Please register in advance of the workshop. Your registration can only be guaranteed once payment has been received. The attendee name must be entered for registration to be complete.

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The BCGS Executive

BCGS EM Workshop 2015

The BCGS is proud to announce its EM Workshop 2015 that will be held at the BCIT Downtown Campus on Friday October 16th. The executive has been hard at work gathering an amazing panel of EM inversion experts who will discuss the latest advances in EM geophysics.
We are putting a slightly different twist on the workshop concept this year as it is going to be an e-poster type, day-long session, where our different experts will be presenting the best of their practical results, rather than a more formal presentation format. The day will start with our opening keynote speaker, Richard Smith, who will give an overview of all the different EM inversion procedures. Then attendees will be divided in small groups and will rotate through the presentations throughout the day. The small size of the groups is aimed at fostering discussion with our speakers and emphasizing the audience participation. At the end of the e-poster session our closing keynote speaker, Alan Jones, will wrap up the day by reviewing what was presented to the audience and what was learned during the day. Everybody will be then invited to join our speakers and the BCGS executive for a social event in a nearby location.

You can find below more details about the event, our sponsors and our speakers.Hope to see you all in October!


The BCGS Executive

Workshop Details

Opening Speaker: Richard Smith Laurentian University
Speakers: Dima Amine Geosoft Inc.
Lief Cox TechnoImaging LLC
Colin Farquharson Memorial University of Newfoundland
Peter Fullagar FGCL Consulting Ltd.
Eldad Haber University of British Columbia
Michal Kolaj Laurentian University
Doug Oldenburg University of British Columbia
Bill Petrick Industrial Imaging Co., Inc.
Phil Wannamaker University of Utah
Closing Speaker: Alan Jones Dublin Institute of Advanced Studies

Date: Friday, October 16, 2015

Time: 8:00 am PST – 4:45 pm PST

Location: BCIT Downtown Campus (555 Seymour St. Vancouver, BC, V6B 3H6, Canada

Admission Cost: Regular $120 / Student $60



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If you would like to sponsor our event, please contact us at

Speaker Bios

Richard Smith:  Laurentian University


Title:  Electromagnetic inversion: challenges and approaches to solutions

Outline:  The presentation will discuss some of the challenge of EM inversion: 1) too little data, 2) too many unknowns, 3) no linear solutions, how to select an initial guess, 4) how to discretize the earth and how to select a solution from the many possible solutions.  The presentation will discuss the different approaches that people have been taken to the EM inversion problem and how each approach is designed in some way to deal with some of the issues.
Dima Amine,  Geosoft Inc.


Title:  A Comparison of Quasi-3D Inversions of Frequency Domain EM Data

Outline:  Full 3D EM inversion requires calculation of the 3D induced current in the earth whereas the Quasi-3D approximations are based on a full 3D inversion but with a simplified, approximate, induced current flow in the earth. We demonstrate two Quasi-3D approximations by comparing their response over the interface of a quarter-space model with the full AEM response, and then demonstrate the methods on a challenging synthetic model and on field data.
Leif Cox,  TechnoImaging LLC


Title:  Practical aspects of large-scale inversion

Outline:  Large-scale inversion requires a somewhat different approaches than deposit scale inversion.  Either computation or physics-based compression must be used to enable practical run times.  Data need to be carefully and often adaptively weighted to ensure uniform fit across all inversion regions.  Model weights should be applied to give uniform importance to each model parameter, both to account for sensitivity variations with depth and variations across different parameters such as conductivity and chargeability.  We describe how to make intelligent choices for these and other parameters of inversion. Case studies represent challenges and solutions in large-scale inversions of the airborne EM data.
Colin Farquharson,  Memorial University of Newfoundland


Title:  Towards Real Earth Models — Computational Geophysics on Unstructured Tetrahedral Meshes?

Outline:  When visualizing and modelling the subsurface in the context of mineral exploration, geologists use 3D Earth models that are made up of tessellated wireframe surfaces. In contrast, we geophysicists have so far used almost exclusively rectilinear meshes to parameterize our Earth models. Wouldn’t it be better if our geophysical models were parameterized in a way that was consistent with – meshed seamlessly with – geological models? An Earth model could then be a single unified, integrated entity that served as both a geological model and a geophysical model. I shall present some examples of the work we’ve been doing to try to achieve this goal and some of the challenges that we face.
Peter Fullagar,  FGCL Consulting Ltd.


Title:  Fast 3D inversion of transient electromagnetic (TEM) resistive limit data

Outline:  A fast 3D inversion scheme has been developed for time-integrated (resistive limit) TEM data. The resistive limit inversion is up to 100 times faster than “rigorous” 3D TEM inversion. The software can advance integrated interpretation by performing inversion on a geological model. The inversion scheme is illustrated via application to airborne, ground, and downhole TEM data.
Eldad Haber:  University of British Columbia


Title:  3D inversion of airborne data

Outline:  In this talk we will show how common airborne data sets can be inverted in 3D in order to give geologically meaningful information,  We use both synthetic and field examples
Michal Kolaj,  Laurentian University
Website:  Inductive electromagnetic data interpretation using a three-dimensional distribution of three-dimensional magnetic or electric dipolesAuthors:  Michal Kolaj1 and Richard Smith1
1Laurentian University, Department of Earth Sciences, Sudbury, Ontario, Canada

Outline:  We invert inductive magnetic field data, at a given fixed-time or frequency, for the causative subsurface current system which we represent with a 3D distribution of 3D magnetic (closed loop current) or electric (line current) dipoles. The methodology is tested on synthetic plate data and two field examples; a deep massive sulfide (mineral exploration target) and a near-surface mine tailings pond (engineering/environmental study).
Doug Oldenburg:  University of British Columbia


Title:  Can airborne IP be valuable for kimberlite exploration?

Authors:  Douglas W. Oldenburg1 and Seogi Kang1
1UBC-GIF, Vancouver, British Columbia, Canada

Outline:  Recent developments in airborne TEM inversion to recover 3D IP structures are applied to Tli Kwi Cho (TKC). We present the basic procedure by which  time channels, that have significant IP response,  are first subjected to an EM decoupling procedure and then inverted to recover a 3D pseudo-chargeability at each time. A subsequent inversion carried out for each volumetric cell recovers estimates of Cole-Cole parameters for that cell. For TKC the recovered decay times for the three rock units PK, HK, XVK, are distinctly different. Laboratory analysis of core samples supports this conclusion.
Bill Petrick, Industrial Imaging Co., Inc.


Title:  Pitfalls in 2D AMT Inversion

Outline:  AMT is a powerful tool for minerals and water exploration.  It is common practice to throw a few AMT (or CSAMT) profiles across a project and hope for the best.  I’ll explain the problems with this exploration approach and a much better way to design an AMT survey.
Phil Wannamaker,  University of Utah, Energy & Geoscience Institute


Title:  Three-dimensional magnetotelluric inversion using deformed hexahedral edge finite elements and direct solvers parallelized on SMP computers.

Authors:  Phil Wannamaker1, Michal Kordy1, Virginie Maris2, Elena Cherkaev1, and Graham Hill3
1UofU – EGI, Salt Lake City, UT, USA; 2Universität Trier, Trier, Germany; 3GNS, Lower Hutt, Wellington, New Zealand

Outline:  We describe a new algorithm based upon deformable hexahedral finite elements solving the electric field for 3D inversion of MT responses including substantial topographic variations. Direct solutions are used throughout, including the finite element system matrix, the jacobians and the Gauss-Newton parameter step matrix. The last step is achieved by transforming to data-space. Field examples utilizing of order one million parameters will be presented, run on single-box, large-RAM, multi-core workstations.


April 2015 Technical Talk

BCGS April Technical Talk – Wednesday April 15, 2015

SPEAKER: Doug McConnell, P.Eng, P.Geoph, DMT Geosciences Ltd.

TITLE: Geophysicists are from Earth, Engineers are from Mars and other controversial theories: Risks related to misconceptions and limitations of engineering and environmental geophysics

DATE/TIME: Wednesday April 15, 2015 @ 4:30pm

LOCATION: Room 451, 409 Granville St (UK Building at Granville and Hastings), Vancouver


DMT has been specializing in geotechnical engineering, environmental and hydrogeological geophysics for 25 years. Geophysics is best presented to the engineer as a risk management tool to identify targets for drilling or other follow up investigation and not a silver bullet solution. Except in a few cases where geophysical results can be used directly in engineering formulas, there is often the need to make assumptions and provide guidance to deal with equivalence in geophysical results.

Working for engineers presents a unique set of communication, economic and technical challenges to the Geophysicist. One of the most significant is integration of geophysical results into geotechnical and other engineering projects. Of course we are not alone in this, the Geotechnical Engineer has similar problems communicating with the Civil Engineer, but that’s another story.

This presentation includes case histories to illustrate some of the challenges, pitfalls, and misconceptions of that work and how they can be overcome. The case histories present examples of multi-method geophysics studies integrating other geoscience data to minimize risk in directional drilling for pipelines, water inundation in surface mines, RQD determination and hazards from karst in construction projects.