Talk About Geophysics!  TAG Webinar Series

EEGS’ Monthly Educational Webinar Series 

EEGS has developed an educational webinar series exploring topics ranging from scientific presentations to a deeper dive into noted authors’ published articles. The webinar series is intended to offer an informal setting and an interactive opportunity to address diverse geophysical topics. Students will be pleased to see that some scheduled topics will focus on career paths, working with advisors, etc. and small business owners will benefit from sessions ranging from business technical tools to client management.

Send Feedback or Suggest a TAG Webinar

If you have questions, email [email protected].  If you'd like to suggest a future TAG Topic or offer to host a webinar, please click here (for a short, online feedback form for EEGS' TAG Webinar organizers).  You do not need to be a member to submit the form, but you will need to register at the EEGS web site (registering is entering your email address and setting up a username and password) to provide feedback.  

All TAG Webinars begin at times based on US Mountain Time Zone. 

March Webinar
"Active and passive underwater surface wave methods"  
March 8, 2023

Title: Active and passive underwater surface wave methods
Speaker:  Koichi Hayashi,  Geometrics/OYO Corporation
Date:  Wednesday, March 8
Time:  3:00 p.m. PT; 4:00 p.m. MT; 5:00 p.m. CT and 6:00 p.m. ET

Registration is Required!  
Register in Advance for this webinar: 
Registrants will receive a confirmation email with the link to join the webinar. 

An explosive source or vertical force at the bottom of water generates seismic wave that horizontally propagates along the bottom of water. The waves are called Stoneley waves and correspond to generalized Rayleigh waves. Low frequency Stoneley waves propagating at the bottom of water propagate with approximately P-wave velocity of water (1500 m/sec) where S-wave velocity of solid layer is higher than P-wave velocity of the water. In contrast, it propagates approximately S-wave velocity where S-wave velocity of solid layer is lower than P-wave velocity of the water and enables us to estimate S-wave velocity of the solid layer by measuring propagation velocity of the Stoneley waves like surface wave methods performed on the ground surface. This presentation introduces the fundamental theory of underwater surface waves and application example of active and passive surface wave methods at the bottom of lake, river and ocean for various engineering and environmental investigations.

Dr. Koichi Hayashi is presently a Senior Technical Manager at OYO Corporation and Geometrics, Inc. in San Jose, California.  Over the past 30 years, he has worked as a research geophysicist focusing on providing better tools and algorithms for near-surface geophysical methods.  He earned a B.S. degree in Earth Sciences from Chiba University in Japan, a M.S. degree in Earth Sciences from the Massachusetts Institute of Technology, and a Ph.D. in Earth Resources Engineering from Kyoto University in Japan.  His main research areas are seismic refraction, active and passive surface waves, finite-difference seismic modeling, and traveltime inversion. He is the author of the SeisImager data analysis suite of programs and has incorporated many of his theoretical developments into the software, making SeisImager one of the premier surface wave, refraction, and downhole data processing packages available today. He regularly presents papers at the major meetings, publishes in journals of EEGS, SEG, SEGJ, and SSA, and serves on scientific commissions. In 2014, he was selected as the SEG Near-Surface Honorary Lecturer, with his talk entitled “Integrated Geophysical Methods Applied to Geotechnical and Geohazard Engineering: From Qualitative to Quantitative Analysis and Interpretation”.  Most recently, he was a contributing author to the textbook entitled “Seismic Ambient Noise”.

 November Webinar

Continuous Marine Seismic Refraction
November 9, 2022 

Title: Continuous Marine Seismic Refraction
Speaker:  Justin Anning, Surrich Hydrographics

Seismic reflection and refraction surveys provide valuable sub-surface information with respect to coastal geotechnical projects. The seismic reflection method maps layers and interfaces, while the refraction method maps compressional rock velocities.

Single channel seismic reflection is referred to as Sub Bottom Profiling (SBP) and the examples shown herein were performed using a boomer seismic source. Utilizing the same survey vessel and positioning system used for the SBP survey, seismic refraction surveys can be performed in a mobile towed configuration, using a small volume airgun and multichannel streamer. We refer to this methodology as Continuous Marine Seismic Refraction (CMSR).

Examples are presented demonstrating the advantages of acquiring both SBP boomer and CMSR.

Justin has been a co-owner of Australian company Surrich Hydrographics since 2012, where they concentrate on coastal hydrographic and geophysical projects. Justin leads the geophysical projects while business partner Andrew Richardson leads the hydrographic survey projects.

Justin has a BSc in Geophysics from Curtin University, Western Australia in 1993. He has been predominantly self-employed. Previous experiences in the industry are beginning to fade from memory however he started on land, experiencing the typically diverse applications that come with shallow engineering geophysics and exploration work. His fondest memories are the groundwater, salinity mapping and diamond exploration jobs he performed during the first decade of his career before the mining boom made things totally hectic, with the GFC in 2008 being a welcome relief.

October Webinar

4D Electrical Resistivity Imaging of Stress-Induced Changes in Secondary Porosity During High Pressure Injections into a Deep Crystalline Rock Formation
October 12, 2022


Title: 4D Electrical Resistivity Imaging of Stress-Induced Changes in Secondary Porosity During High Pressure Injections into a Deep Crystalline Rock Formation
Speaker:  Tim Johnson, Pacific Northwest National Laboratory
Date:  Wednesday, Oct. 12
Time 3:00 p.m. PT; 4:00 p.m. MT; 5:00 p.m. CT and 6:00 p.m. ET

Fluid flow through fractured rock systems is governed in large part by the distribution, interconnectivity, and size of fracture apertures. In-situ stress isone of the primary factors controlling fracture aperture, and one that is altered significantly during high-pressure fluid injections or extractions. Interactions between stress, pore pressure, aperture, and fluid flow can result in complex and evolving poroelastic behavior with significant implications regarding the predictability and risk involved with developing and managing deep subsurface reservoirs (geothermal, fossil energy, and geologic carbon sequestration).

In saturated rocks, bulk electrical conductivity is sensitive to both primary and secondary porosity (i.e. matrix porosity and fractures), and therefore to fracture aperture size and distribution. We demonstrate the use of time-lapse 3D electrical resistivity tomography for remotely monitoring stress induced changes in aperture distribution during high pressure injections into a dense fractured rock system at a scale of tens of meters. Results reveal a complex and continuously evolving stress field involving aperture dilations in the natural fracture system and aperture contractions in adjacent zones of shadow stress. Results provide information about the spatiotemporal changes in the system behavior and point to the potential of electrical imaging for autonomously and remotely monitoring evolving stress conditions by proxy through changes in bulk electrical conductivity.

 As a reminder, send in webinar topics you'd like to see or indicate your interest in presenting using this feedback form:  Click here!    

2022 TAG Webinar Presentations History

June 2022 TAG Webinar:  Investigation of Scale-Dependent Groundwater/Surface-water Exchange in Rivers and Lakes by Gradient Self-Potential Logging: Numerical Modeling and Field Experiments 

Scott J. Ikard, U.S. Geological Survey, Texas Water Science Center presented his award-winning "Investigation of Scale-Dependent Groundwater/Surface-water Exchange in Rivers and Lakes by Gradient Self-Potential Logging: Numerical Modeling and Field Experiments" which was named the 2021 Alan Witten Best Paper, recognized at SAGEEP 2022. 


May 11, 2022 TAG Webinar:  A Framework for linking Geophysical and Geotechnical Observations

Mark Vardy, MSci. MRes PhD of SAND Geophysics outlined a proposed framework that can be used to link geotechnical and geophysical observations in a semi-quantitative manner not to be considered a definitive method or workflow for translating geophysical observations into equivalent geotechnical observations but rather, to be considered a geoscience Babel fish, bridging the communication gap between geophysicists and geotechnical engineers, allowing users/interpreters to understand how observed spatial and/or stratigraphic changes in one set of parameters are likely to be reflected in other parameters.  EEGS is grateful to Dr. Vardy for presenting and the questions answered at the conclusion of his presentation.


2022 TAG Webinar Presentations History

April 13 TAG Webinar:  A Multi-Geophysical Case Study of a Karstic Aquifer 

Mustafa Saribudak, Ph.D., Environmental Geophysics Associates (EGA), presented his case study on Barton Springs, a major discharge site for the Barton Springs Segment of the Edwards Aquifer and is located in Austin.  On behalf of EEGS and the large TAG Webinar audience, Dr. Saribudak was thanked for the presentation and follow-up question and answer session.

2022 TAG Webinar Presentations History

February TAG Webinar:  Leading the Way to Inclusion

Julia Potter, Call & Nicholas, Inc. and Mario Munoz, University of Arizona presented the latest news and accomplishments of the Arizona Chapter of Women in Mining, which focused on diversity, equity and inclusion (DEI) in the mining and mineral resources industries.  They also shared how individuals can contribute to more inclusive organizational cultures.  An engaging question and answer session followed.  Moira Poje, chair of EEGS' Diversity, Equity and Inclusion Task Force, thanked the February TAG Webinar presenters Julia and Mario for their inspiring and informative presentation.

2022 TAG Webinar Presentations History

January TAG Webinar: Geophysical Exploration of a Historical Stamp Mill Dump for the Volume Estimation of Valuable Residues

Tina Martin, 2020 Alan Witten Best Paper award winner, presented her paper "Geophysical Exploration of a Historical Stamp Mill Dump for the Volume Estimation of Valuable Residues" during a well-attended January webinar.  Presented was an approach for the estimation of ore processing residue volumes in a historical mine waste dump by combining electrical resistivity tomography (ERT), ground penetrating radar (GPR) and spectral induced polarization (SIP) flanked by mineralogical studies, enabling Ms. Martin and her colleagues to distinguish between valuable and non-valuable waste material and to calculate the volume of the ore processing residues, which can be used further for the determination of the economic potential from the remaining metal content.  (The Journal of Environmental and Engineering Geophysics (JEEG) offers an opportunity for published authors to earn a yearly Best Paper Award in honor of Alan Witten. The Best Paper Award is decided by the EEGS board of directors after a recommendation from the current JEEG editor. The award is presented yearly at SAGEEP.)

2021 TAG Webinar Presentations History

December TAG Webinar:  Best of the Proximal/Remote Sensing Soil Investigation Symposium

Harrison Smith (University of Arkansas), Felippe Hoffmann Silva Karp (McGill University), and Steven van der Veeke (University of Groningen) served as December's TAG Webinar presenters.  The three presenters were the “Application of Proximal and Remote Sensing Technologies for Soil Investigations” virtual symposium's best student presentation award winners.  The virtual symposium was a collaborative effort between the International Union of Soil Sciences – Proximal Soil Sensing Working Group, the Society of Exploration Geophysicists, and EEGS.  Approximately half of the 45 research presentations given at this symposium were provided by students, their quality termed by the Technical Committee as "outstanding."  EEGS was proud to feature the winners at its December TAG Webinar, and, based on the Q&A session and feedback, very well received by the webinar participants!   

November TAG Webinar:  Careers in Near-surface Geophysics

A panel of six professional geophysicists led a discussion on their careers and trends in geophysics on Nov. 10.  Bart Hoekstra, Dan Glaser, Esther Babcock, Evgeniy Torgashov, Katherine Grote, and Craig Murray represented a wide range of positions and roles in geophysics and shared their experience, education and professional development path with participants.  Great questions, as one panelist termed them, were posed by participants, adding to the value of the experience.     

October TAG Webinar: GeoLatinas presenters and members

On October 13, EEGS welcomed Adriana Crisóstomo Figueroa and Alma Vázquez-Lule of GeoLatinas to TAG Webinars.  GeoLatinas is a grassroots organization building bridges towards equity, diversity, inclusion and accessibility in the geosciences.  EEGS' Task Force DEI (Diversity, Equity and Inclusion) Chair, Moira Poje, hosted the event, presided over the question and answer session and thanked the presenters for their informative overview of GeoLatinas, its work to inspire and support those currently engaged or working in earth and planetary sciences, and impressive list of initiatives and accomplishments.     

September TAG Webinar - Magnetic Surveying for Man Made Objects – Theory 

On September 8, Gretchen Schumauder and Bart Hoekstra hosted a pre-recorded presentation by Becky Bodger, Seequent Limited, and Stefan Burns, Bart Hoekstra and Gretchen Schumauder from Geometrics Inc. This was the first in a series about magnetic surveying for anthropogenic objects and focused on the practical implications of magnetic theory for conducting surveys.  Following the pre-recorded presentation was a question and answer session hosted by Gretchen and Bart.  

August TAG Webinar - G2HE - Transforming Geophysical Parameters into Hydrogeological and Engineering Parameters and the Relevance of the Factors of Empiricism, Scalability, Resolution, Uncertainty, Clay and Experience

On August 11, attendees participated in EEGS' August TAG Webinar and an extended question and answer period.  Organizers thanked Mr. Pettifer for his interesting title and informative presentation.  

July TAG Webinar - Characterizing a Physical Model of a Collapsing Void Using a Trapdoor and Time-Lapse Surface-Wave Analysis

On July 14, Sarah Morton Rupert presented findings from a laboratory text box using a physical model designed to simulate void roof failure and migration to the ground surface to support the conceptual model that Vs variations can be an indicator of stress-field variations in the roof structure above a void and used to map the progression of a collapsing structure.  Questions and Ms. Morton Rupert's responses rounded out the well attended webinar.  Organizers and attendees thanked Ms. Morton Rupert for presenting her award-winning presentation with EEGS TAG Webinar participants.   

May TAG Webinar - New Frontiers in Near Surface Geophysics: Muons, Cosmic Ray Neutron Probes, and Hyperspectral Imagery

On May 12, Leon DuPlessis, formerly with Freeport-McMoRan Inc., Trenton Franz, Univ. of Nebraska, and Isabel Barton, Univ. of Arizona presented three very interesting and informative talks and answered participants' questions.  Dr. DuPlessis spoke about Subsurface Density Mapping Using Muon Technology; Dr. Barton presented Mineral Mapping Using Drone-Based Hyperspectral Imaging;  and Dr. Franz summarized the Opportunities and Challenges Towards Integration of Hydrogeophysical Sensors in Agriculture.  TAG Webinar organizers expressed their appreciation to all three presenters for a very well received event.

April TAG Webinar -  Proximal Soil Sensing: State of the Science

Dr. Craig Lobsey, senior lecturer in mechatronic engineering at the University of Southern Queensland, University of Southern Queensland presented his perspective on some of the key challenges in the application of sensor technology for soil management, recent developments and what may be on the horizon for proximal soil sensing technology.  Organizers extended many thanks to Dr. Lobsey for his talk as well as a robust question and answer session which followed.  

In March, EEGS held SAGEEP 2021 - held virtually March 14-19, 2021.

February TAG Webinar - Meet Me Halfway

The EEGS Task Force Diversity, Equity and Inclusion (DEI) takes advantage of every opportunity to raise awareness and take a lead role in setting and achieving the highest standards of integrity, fairness, dignity and respect. Therefore, February's TAG webinar series featured a Task Force DEI webinar:  Meet Me Halfway, an interactive webinar exploring intergenerational communication in a geophysics workplace.  EEGS President Barry Allred commented: "Thanks to all the Task Force members for your efforts putting together the TAG webinar. It was excellent, well organized, and the discussions in the breakout rooms were very interesting and insightful.  I think everyone really enjoyed the interactive webinar format."

The webinar slide presentation is available for viewing by clicking here.

Inaugural January TAG Webinar a Success!

TAG's first webinar was held on January 13 and welcomed guest speaker, G. Didem Beskardes, the JEEG's 2019 Alan Witten Best Paper Award recipient.  By all measures - audience participation, attendee feedback and content quality - the TAG Webinar was successful and well received.  Dr. Beskardes discussed her findings from the study published in the JEEG paper "Power Density Distribution in Subsurface Fractures Due to an Energized Steel Well-casing Source" and conducted a lengthy and insightful Q&A session.