Interviews

An interview with Mirko Van Der Baan

Photos courtesy: Ashly Ashokan
Mirko Van Der Baan

Mirko van der Baan is a Professor of Exploration Seismology at the Department of Physics, University of Alberta at Edmonton. Prior to this assignment he worked at the Institute of Physics of the Globe, Denis Diderot at Paris as a visiting professor, and as a lecturer at the University of Leeds in UK. His research interests involve signal processing, microseismicity and seismic wave propagation in anisotropic media. He also runs two industry-funded consortia at the U of A, namely BLISS (Blind Identification of Seismic Signals) and the Microseismicity Industry Consortium.

Mirko is a well-published author. He has been invited to several international seminars, and is on the editorial board of Geophysics. The presentations that Mirko and his students make at international conventions are always well-received. In particular, their presentations made at the SEG in the last 10 years have been adjudged in the top 30 four times out of all the several hundred presentations made each year, which is very creditable.

When the RECORDER approached Mirko for an interview, he took long in getting back but agreed, saving us the usual persuasion to many interviewees. Following are excerpts from the interview.

Please tell us about your educational background, employment and experience?

I graduated from Utrecht University in the Netherlands with the equivalent of an M.Sc. degree in Geophysics; next went to Grenoble, France where I learned to climb and ski and also got a Ph.D., then on to Leeds in the UK for a postdoc which ultimately turned into a Readership, and also learned some pub culture. Since 2008 I’m in Edmonton, Canada, as a professor in the U of A Physics Department. Along the way I also obtained a habilitation in Paris, France. During my education I had the pleasure of being advised or supervised by Everhard Muyzert and Roel Snieder (M.Sc.), Georges Poupinet and Anne Paul (Ph.D.), Mike Kendall (postdoc), Satish Singh (habilitation).

How did you decide to get into geophysics when you started studying for your graduation?

At the end of school I figured I had a knack for the exact sciences but I thought most of them were too abstract and didn’t involve phenomena I really wanted to get my hands dirty with. So my oldest brother introduced me to a friend of his, Hendrik Jan van Heijst, who was doing a Geophysics degree at Utrecht University. Hendrik Jan took me along for a day and hooked me to topics like mountain building (tectonophysics) and earthquakes (seismology).

How come you decided to go to Grenoble for your Ph.D. in Geophysics?

My parents must have infected me with a travel bug (when I was young I also lived for four years in Germany) so when I had nearly completed my M.Sc. degree I was keen to explore the world outside of the Netherlands a bit and looked into opportunities to do my Ph.D. abroad. In the end I chose Grenoble but funnily enough Canada (Queen’s) and the UK (Leeds) also figured on my horizon. I had met Georges Poupinet who sold me to the idea of a thesis that combined observational and theoretical seismology, looking into repeating earthquakes (multiplets) in a dataset from Quito, Ecuador. In the end I switched datasets and topics but I have used those multiplets in microseismic data for a variety of purposes since.

You spent a fair bit of time at the University of Leeds. Tell us about what all you researched on there.

I seem to have a habit of looking into new topics every couple of years (the grass is always greener on the other side of the road so new topics are highly enticing). I have published on anisotropy, attenuation, microseismicity, shear-wave splitting, multiplet analysis, sub-basalt imaging, common conversion point sorting and probably a couple other topics while at Leeds.

I don’t remember why (probably lack of funding) but a Ph.D. with Mike Kendall in Leeds didn’t work out. Nonetheless, at the end of my Ph.D. I contacted Mike again to hear if he had any postdoc opportunities. Mike had just secured funding from Shell to work on anisotropy parameter estimation. So I changed my Ph.D. research topics (signal processing and multiple wave scattering) and started working on wave propagation in anisotropic media. Mike also set up his Leeds Anisotropy and Microseismicity Project at that time (in 2000, far ahead of the popularity it now has) with the result that he got me hooked to microseismicity early on.

Just to show it’s a small world, I shared an office with David Eaton when he spent part of his sabbatical in Leeds. When I moved to the U of A, Dave had just moved to the U of C to become the Chair of the Geosciences Department (I never know if I should congratulate people when they become Chair since it is a very important but extremely time consuming role). I was keen to set up new collaborations when in Edmonton and with Dave we created the Microseismic Industry Consortium in 2010.

Since 2008 you have been at the University of Alberta. How has the migration been for you so far? Would you like to tell us about the work cultures at the two universities?

Canada has been treating me very well. I am always impressed with how friendly and helpful Canadians are. My personal philosophy is that winters are so long and cold that people are just happy to chat, relax instead of rushing around. Research-wise, I am busier than ever due to the significant academic, public and industrial interest in microseismicity and induced felt seismicity.

The UK and Canadian university cultures are quite different. A significant portion of university funds in the UK come from overheads (indirect costs). This means that promotions are determined by esteem, research and teaching quality and grant funding. In Canada overheads are low which means that it is less important to the University how much funding you bring in but on what you do with it. In other words, emphasis is on the quality of science and research, less on the number of dollars. There also seems to be a greater emphasis on teaching quality or student satisfaction, depending on your point of view.

What is it that you love about teaching and researching at the university?

I like the interaction with the students and postdocs, to see how they digest and learn new topics, as well as grow in their careers (hopefully I contributed positively!). I also greatly appreciate the academic freedom to constantly explore new topics (grass, green, other side). In essence, academics are small business owners, in that we decide what topics we are going to explore instead of a boss higher up. On the flip side of the coin, we are also directly responsible for our own successes, failures, administration, etc.

We all basically have a driving goal in life. What has it been for you?

It may sound like a cliché but it’s probably knowledge. I greatly enjoy learning and exploring new topics.

So far, what career accomplishments are you most proud of?

That’s a difficult question. It’s one of my standard interview questions, but not always easy to answer. Obviously I greatly appreciate the interest and feedback generated by the Microseismic Industry Consortium. I also enjoy hearing if someone particularly appreciated one of my papers. I guess I am proudest though if I hear from former students and postdocs (affectionately called our academic babies by my wife) that I helped their careers.

Tell us about some of your memorable moments in your professional life and also a success story you might want to share with us, if the two are different?

When Dave Eaton and I were rounding up industry support for the Microseismic Industry Consortium we secretly hoped we could get 8 sponsors. We were completely taken back when 17 sponsors joined in the first year. For the last three years there have been 29-31 sponsors which went beyond our wildest expectations.

This amount of funding has allowed us to look into a diverse range of scientific topics, some of which have had surprising applications. For instance we discovered that resonance frequencies in microseismic data can mimic fluid-injection parameters (internally known as ‘how to spy on your completion engineer’). It turns out this has been picked up by the glaciologists to look at fracture opening and closing deep inside glaciers.

How many undergrad and grad students have you supervised so far?

15 postdocs, 17 MSc/PhD students, around 35 course-based MSc students, and 7 undergrads.

Tell me about Mirko, the person – i.e. your habits, your likes/ dislikes, etc.?

One of the attractions for moving to Edmonton was that I hoped it would allow me to spend more time on skiing, climbing and walking in the Rockies. Canada is really compact on Dutch maps, but less so in reality (funnily enough, the Netherlands is really vast on those same maps). So unfortunately this hasn’t materialized as much as I’d like to (I managed to ski one day this year and that was in Switzerland). I still walk between home and my LRT stop (around 15 mins) also in the depths of winter, just to get some fresh air and clear my mind. I also greatly enjoy photography which might be why I often pick up on small details in student work or my research.

So what areas of geophysics do you like better than others? Do you plan to focus on research on these areas or you would like to pick up whatever catches your fancy?

Every couple of years my fancy wanders… Did I mention green grass on the other side of the road?

What personal qualities do you think helped you achieve all that you have achieved? Please share with us one or two of your most exciting successes?

Everyone loves talking about successes, forgetting there are lots of struggles and even failures along the way. So let me talk about one research idea I had that lead to six months of frustrations.

I thought it should be possible to remove geometric spreading by applying a plane-wave decomposition, such that the remaining amplitudes should be exactly equal to the reflection coefficients. I tested the idea on some synthetic data I had created and it didn’t work. In these cases you never know immediately if the idea is wrong, it’s implemented incorrectly (meaning you overlooked something) or there is a bug in your codes. So I created new synthetics using a reflectivity method and now it did work. After more testing, it worked for reflectivity synthetics but only sometimes for ray-traced synthetics. Closer scrutiny showed ray-traced and reflectivity synthetics could produce different reflection amplitudes. I then did what most people do at this point (call/email friends, not yet give up) but none of them could tell me what was going on. I then decided it might be useful if I programmed up my own reflectivity method just to understand the theory better (yes I went on a complete tangent, not that unusual in academic circles).

Mirko Van Der Baan

Six months later I had a half working reflectivity method, a lot more respect for those who manage to create working ray-tracers or other complex wave propagation codes, had looked into numerical integration methods, approximations to Bessel functions, plane-wave versus spherical reflection coefficients, refractions versus geometric ray theory, and probably more items I have happily forgotten since. To end a long story, ultimately I figured out that the Zöeppritz reflection coefficients include also the contribution of the refraction (head wave) which splits from the reflection in the time domain. Ray-tracers don’t handle this situation correctly and provide incorrect amplitudes around the critical angle. Obviously when I told the same friends that I figured it out, they all said this was well known and they could have told me this directly… (they are still friends). All of this led to the grand total of one paper.

What are your aspirations for the future?

Be happy, explore more science.

What are the directions the R & D in our industry are focused? Any particular revolutionary technology around the corner that will help us in a big way?

Surprises are always just around the corner. In the last 10-15 years enormous strides have been taken to make development of unconventional, tight resources possible; as a result the USA is now the largest oil producer in the world. In the current economic climate, the question will be how to do this cheaper without sacrificing sustainable development.

What in your opinion are still the three most important unsolved problems in geophysics?

  1. Finding a good work-life balance
  2. Finding an optimal balance between economic and sustainable development of our precious resources
  3. Understanding why and when felt induced seismicity may occur. Contrary to some high-profile publications, felt seismicity due to anthropogenic activities is rather an exception than a general rule given the scale of hydrocarbon exploitation in North America. It does occur though. It is important for all (operators, regulators, the public and academics) to understand better the underlying processes.

Amongst the various problems you have worked on, I found seismic wavelet estimation, non-stationary phase estimation, anisotropy parameter estimation, Q-compensation, imaging of sub-basalt structures using converted waves as very interesting and relevant for the seismic industry. Tell us about each one of these and what your motivation was in pursuing them.

Often pure scientific curiosity but also opening up or conversely drying up of industrial funding. My original postdoc topic was on anisotropy because of strong industrial interest at the time. We also looked at microseismicity because BP provided us with a dataset from Valhall (a subsiding reservoir which led to 1-2 well failures per year in the 80s). When industrial interest in anisotropy faded in the mid 2000s, I set up the BLISS consortium on signal processing to work with Christian Jutten (whom I met during my Ph.D.) on independent component analysis and blind deconvolution. While at Leeds, Roger Clark got me interested in seismic attenuation. In Canada I picked up the topic of microseismicity again because of significant industrial interest.

The students and postdocs in my group are another great source of inspiration. The all have their own interests and often bring bright new ideas which we then try to apply on geophysical topics.

Do you think new geophysical technologies hold the promise of extraction of more information for characterizing unconventional hydrocarbon reservoirs?

Definitely, but I don’t have my crystal ball ready to tell you what method will be the winner.

On a lighter note, please permit me to ask you this. What differences did you notice when you turned 30 years, 40 years and 50 years? As an example, some people think 30s allowed them to experiment with options, 40s gave them time for self-introspection, some get naughty at forty. Your comments?

If I look back I think I had a tendency to look at things more in black and white when I was younger (it was right or wrong, science was all about numbers, etc). Now I am more aware and understanding of the human aspect (earthquakes are as much about stories, experiences as well as the topic of scientific investigations; lots of emotional reasons and stress may drive students to commit academic misconduct). Hopefully this will allow me to develop color-vision when I turn 50 (not for quite a few years yet). I believe with growing experience we become better scientists who can understand both the details but also the wider implications, for science and society in general. I’m convinced I would have a blast if I would miraculously find myself back at university or school with what I know now…

What are your other interests?

Besides dreaming of skiing, climbing and walking in the mountains, I enjoy traveling for holidays (not business), reading good books and comics, and spending time with my lovely wife.

Do you have any words of advice or inspiration for young people considering a career in Geophysics?

A few years ago I met Charles Stelck who gave me the advice that you should never allow yourself to be boxed in, meaning you should always strive to explore new topics, learn new fields, be open minded, and reinvent yourself if your career or outlook becomes stagnant.

End

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