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KEGS December Bulletin

4 Dec 2023 8:46 AM | Peter Tschirhart (Administrator)

KEGS Foundation Jerry Roth Student Symposium

The link is live for the Jerry Roth Student Symposium! Please register your seat here:


Date: Tuesday, December 5th

Time: 1:30 pm - 5 pm

Location: University of Toronto, Earth Science Building, Room #2093 at Huron and Russell.

Cost: Students - Free, Professionals - Donations appreciated. Donations above $25 will receive a charitable donation receipt.

The KEGS Foundation would like to invite you to attend the inaugural symposium in honour of our late Chairman, Jerry Roth, who passed away in February 2023. Jerry was a champion of students and supported them through the formation of the KEGS Foundation, and awarding scholarships, but also by encouraging their participation in academic conferences, professional society presentations and general networking. Please join us on the afternoon of December 5th for student talks and networking. Let’s honour Jerry’s memory by encouraging the next generation of students in geophysics.

All attendees are strongly encouraged to register and attend the KEGS Xmas party immediately following the event. All are welcome! Come out, support students and help us pay tribute to Jerry Roth.

KEGS Holiday Social & Gathering

Please join us for our annual Holiday Social on Tuesday, December 5th, 2023, at the Duke of York Pub.


The event will follow the Inaugural Jerry Roth Student Symposium to be held a short walk away at the University of Toronto, Earth Science Building, Room #2093 at Huron and Russell (1:30 pm to 5 pm)

We'll toast the past year and celebrate the season as we catchup with friends and colleagues. 

Date: Tuesday Dec 5th at 5:30 PM

Location: Duke of York Pub, 39 Prince Arthur Ave, Toronto, ON M5R 1B2


Upcoming KEGS talks and events

KEGS is currently looking for speakers for the Spring 2024 meetings. If you are interested to speak at a KEGS monthly talk, please contact any of the Executive.

Upcoming talks and events:

  • December Events - 5 December: KEGS Foundation Mini-Symposium (1:30pm to 5:00pm, U of T) & KEGS Christmas Party (5:00pm, Duke of York) - Details below
  • January Talk - 9 January: Jim Craven (Geological Survey of Canada) - A Conservative Approach to Inversion with AI.
  • February Talk - 13 February: Omid Bagherpour (BHP) - Title TBA. 
  • March Events - 2 March: KEGS PDAC Symposium - Abstract deadline is Friday 1 December, 2023. Further info here.

Find out about more geoscientific events in GTA Geoscience calendar here.


2024 New KEGS Executive Member

Do you want to give back to Canadian Geophysics community? Do you have good ideas on how to grow the community and support geoscience students? Do you have a deep longing to be part of another committee? Well, KEGS has an open slot for a new executive member starting in January 2024. 

If you have any interest, and want to find out more about what is involved, please reach out to any of the current executive (contact details below). 


KEGS Ottawa

Please join us for our final presentation of 2023 and some holiday social time at a pub afterwards. Spread the word; be sure invite anyone you think might be interested.

KEGS Ottawa December Meeting

Speaker: Marc Valée, Geo Data Solutions GDS Inc.

Title: AEM interpretation with the sphere model

Abstract: Airborne Electromagnetic (AEM) data interpretation is a complex process. Physical property distribution inversion, which has been developed for other techniques such as magnetics and gravity, is difficult to apply to AEM data on a routine basis. Data noise and complexity of Maxwell equations make inversion process costly and ill-constrained, with the possibility of multiple solutions. An alternative method of interest in brown field exploration is the use of parametric models, such as a plate or a sphere. A sphere in free space is the oldest electromagnetic model used in mineral exploration. It can be integrated in a parametric inversion and automated to handle survey interpretation. However, it is not appropriate in situations where overburden or/and host rock are conductive. To address this problem, we developed a solution for a sphere in a layered earth. Original mathematical developments were used in this solution. Using field expansions resulting from derivative solutions of the cylindrical functions, which describe the fields propagating in the layered earth, and spherical functions, which describe the fields reflected by the sphere, we developed relationships between cylindrical and spherical functions. The secondary field originating from the sphere is estimated in the following way: the incident fields from the AEM transmitter are propagated with cylindrical functions using the Hankel transform to the surface of the sphere; the incident spherical field is estimated using spherical harmonic analysis; spherical reflection coefficients are applied to compute the spherical reflected fields; these reflected fields are transformed from spherical to cylindrical expansions using the spherical-function-cylindrical-function relationship; and the resulting field is propagated with cylindrical functions to the receiver using Hankel transform, while correcting for the reflection of the sphere on the layered earth. With appropriate layered earth reflection and transmission coefficients, the sphere can be located anywhere in the layered earth. This model has been linked to a SVD non-linear least square inversion using a modified Gauss-Newton-Marquardt method in order to invert for the sphere or/and the layered earth parameters. The model and the inversion have been tested on synthetic and field data, in particular data collected with the AirTEM system over Reid-Mahaffy, Ontario, test site. Results from these tests show the value of integrating the sphere in a layered earth model in the AEM interpretation toolbox.

As we were concerned in the validity in our algorithm, we developed for magnetotelluric modelling a public domain program, available in Fortran and Python, using the same computer functions. This program allows a comparison of the results of our model with results of numerical solutions and is available on request.

Bio: Marc Vallée graduated in geological engineering from Laval University, before completing a master’s degree in geophysics at the University of Toronto, and a Ph.D. in geophysics at École Polytechnique de Montréal. He has over 30 years of experience as a research scientist in applied geophysics, mainly for the Noranda Technology Center, then for Fugro Airborne Surveys and CGG companies. From 2015 to 2018, Marc was responsible for magnetic and gravity geophysical inversion as part of the NSERC-CMIC Footprints project. Since then, as AEM Expert & Marketing, he is responsible for geophysical research and development for Geo Data Solutions GDS. His expertise is mainly in the processing and interpretation of airborne electromagnetic, magnetics, gravity, and spectrometry surveys, as well as software development. Marc is the author or co-author of more that 50 scientific articles in applied geophysics.

When: Monday, December 18, 4:30 pm

Where: at the GSC, Harrison Hall, Room, Room 177, 601 Booth St, Ottawa

Please note: In order to enter Harrison Hall, you will have to show some Canadian ID: a passport, permanent resident card, driver license, or health card. If you are a foreign student and have a residency visa, that should work too. Send me an email if you are not Canadian and have some questions about whether your id will work. The reason for this extra complication is that Harrison Hall is inside the controlled area. Checking everyone's id documents might take time - please try to get on site with some time to spare for the extra security procedure.

Upcoming KEGS Ottawa Presentations:

  • Monday, December 18: Marc Vallee, Geodata Solutions, “Electromagnetic sphere in a layered earth model: theory and applications”
  • Monday, January 15: Taylor Tracy Kyryliuk, uOttawa, “The Aquarius Ocean Bottom Seismometer"
  • Monday, February 19: Chris Galley, uOttawa, “Satellite-derived gravity data: from ocean wide bathymetric mapping to crustal scale modelling"
  • Monday, March 18: Dennis Gamble, Notra Inc.,"UXO case history: From initial site assessment of the former Utopia, NB army base (370 km2) using a mineral exploration approach to develop an Unexploded Ordnance Site Model (SUM)".
  • Monday, April 21: Bob Grasty, GammaBob, “Experience building a worldwide network of calibration pads for ground and airborne gamma ray surveying"

Please contact Luise Sander, SGL,, (613) 521 9626 for:

  • any upcoming KEGS Ottawa presentations
  • if you know anyone who might be interested in presenting to our KEGS Ottawa group
  • if you know anyone who should be included on the KEGS Ottawa email group
  • if you are on the KEGS email group and would like to unsubscribe from it

KEGS PDAC Symposium 2024

Mark your calendars - KEGS is excited to announce the return of the annual Symposium to be held the Saturday preceding the 2024 Prospectors and Developers Association of Canada (PDAC) Convention in Toronto, Canada. The event is planned to be held in person on March 2nd, 2024.

Abstract submission deadline is the 1st of December!

Further information and abstract submissions at the KEGS website

KEGS Foundation Update

1. The 5 à 7 event in Quebec City on November 22 attracted fifty people, including a number of students and professors, and was reportedly quite enjoyed by all. Thank you again to our sponsors: Géostack, Géophysique GPR, Abitibi Géophysique and Instrumentation GDD. And sincere thanks to the event organizers: Circé Malo Lalande, Christian Dupuis, Martin Blouin and Jean Legault.

2. As the season of giving is upon us, please consider the KEGS Foundation. We thank family and friends of Jerry Roth, and Teck Resources Limited, for recent donations.

Additional details can be on the Foundation’s website.


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