“Dive into the vastness of geophysical sciences...”

An interview with Mostafa Naghizadeh

Coordinated by: Satinder Chopra | Photos courtesy: Joyce Au
Mostafa Naghizadeh

Mostafa Naghizadeh is a postdoctoral fellow at the Department of Physics, University of Alberta and the winner of 2011 SEG J. Clarence Karcher Award. Mostafa worked on applied seismology as part of the Signal Analysis and Imaging Group under Dr. Mauricio Sacchi's supervision. Prior to his return to the U of A, Mostafa spent two years as a postdoc at U of C, working with CREWES, the Consortium for Research in Elastic Wave Exploration Seismology.

Mostafa is known for his development of algorithms for reconstruction of regularly and irregularly sampled and aliased seismic data. His work has been studied worldwide because of its importance in solving the ubiquitous seismic imaging problem.

and has made presentations at the CSEG, SEG and EAGE conventions and at meetings with R & D industry collaborators. He has received numerous awards for his presentations that include the 2006 Honourable mention for best student paper for CSEG/CSPG/CWLS Convention, 2007 Best student geophysical paper award at the CSEG/CSPG convention, 2008 SEG best student poster award, 2009 Best student geophysical oral presentation (CSPG CSEG CWLS Convention) and the 2009 Andrew D. Baillie award (CSPG).

Mostafa gladly accepted a request for an interview with the RECORDER. The following are excerpts from the interview.

Mostafa, let us begin by asking you about your educational qualifications and your work experience.

I started my post-secondary education with an undergraduate degree in Mining Engineering at Sh. Bahonar University of Kerman. Then, I embarked on my graduate studies with a master's degree in Geophysics from the University of Tehran. I continued on with my graduate studies by entering the Ph.D. program in Geophysics at the University of Alberta. I obtained my Ph.D. degree in geophysics (exploration seismology) under the supervision of Dr. Mauricio Sacchi in 2009. Then, for two years I worked as a postdoctoral researcher with CREWES at the University of Calgary under the supervision of Dr. Kris Innanen. Currently, I am back at the University of Alberta collaborating with the Signal Analysis and Imaging Group (SAIG) as a postdoctoral fellow. As for work experience, I have worked in various earth science related areas during my academic career. This includes summer jobs in Coal and Kaolin mines during my B.Sc. degree, collecting Magneto-Telluric data during two summers of my M.Sc. degree, working for three months as a field geophysicist at a seismic survey in southern Iran, and a summer internship with CCGVeritas Calgary in 2008. Also, recently I have completed contract works with some processing companies by writing industrial multidimensional seismic interpolation programs.

So after doing your B.Sc. with a focus on mining engineering, how did you decide on pursuing geophysics for your Masters?

My engineering degree was an amazing journey learning about a wide range of areas in geosciences. I studied geology, mineralogy, geophysics, surface and underground mining, surveying, transportation and ventilation in mines, blasting, mineral processing, road building, and much more. However, for my graduate studies I wanted to be more focused. Among the myriad of topics that I learned about in my undergraduate studies I found geophysics very interesting. I liked physics and mathematics and I was doing very well in related courses. Geophysics seemed to be an area where I could utilize my skills in math and physics.

After your Masters, what made you come to Canada, and to U of A of all other universities?

I was interested in studying abroad and Canada's academic institutions were among the highest ranked universities in the world. I also applied to a few universities in the USA. In researching the work that several different professors were pursuing I was very impressed by Dr. Sacchi at the University of Alberta. In addition to getting admission to a university abroad I also had to obtain a study VISA. My VISA application for the USA was delayed, however I was happy that the process for my Canadian VISA was timely and smooth. And here I am now interviewing with the RECORDER.

You had been a top student during your B.Sc. and M.Sc. as per your GPA average. How do you think you got that?

During my undergraduate studies it all had to do with passing my courses with high grades! I would just focus on the material presented in the courses and work to understand them as thoroughly as possible and perform my best at exams. However, during my M.Sc. degree I made a shift in my studying style and learned how to really do research. I would do my own inquiries into the topics that were being covered by the instructors. This period helped me to a great extent to understand the science, how it works, and what makes her a very unique source of knowledge. Of course I needed to spend more time on my studies but the personal satisfaction that I was getting from my inquiries was really worth it. This was also reflected in my grades. My new look at science also created a big shift in everyday life and beliefs. I value the latter way more than my GPA.

Recently, at the 2011 SEG meeting at San Antonio, you received the J. Clarence Karcher Award. Tell us how you feel after having received this award, which is given to a young geoscientist for exceptional contribution to geophysics. What does it mean to you?

It's difficult to find the words to express how I feel. I was very grateful for the nomination and I was honored and humbled to receive such a prestigious award. This award allowed me to reflect on my research and motivated me to continue my endeavors in geophysical research.

Awards are not new to you as you have been getting them for some of your presentations at Conventions. How do you maintain this tempo?

I am continually inspired by those around me – my instructors, my family, my colleagues, and my mentors. I love the work I do and anytime I come up with a solution to a problem I am very fulfilled. Again I am honored that others see this in me as well and nominate me for these awards.

Tell us about Mostafa the person in five words?

Dedicated, fun, active, rational, caring.

Now elaborate on these five words?

Dedication is the essential ingredient for progress, invention and finding viable solutions for noteworthy problems. If one chooses work that one likes then work is fulfilling and can even be considered fun. It is also important to have balance and have fun in life too. I have a good sense of humor and try not to take myself too seriously. I believe one should keep equilibrium between hard thinking work and physical work. Staying active and exercising is important to keeping that equilibrium. I enjoy playing soccer whenever I can. I am also a rational person. I use a lot of science and rational thinking for solving problems in my scientific tasks and work. These can be equally applied for everyday life and enrich the life experience. I am also a caring person and have empathy for others' feelings. So it is of a great importance for me to make sure that I can minimize any harm that my actions in life can have on others. I might call it a modern rationalized version of Confucius' golden rule.

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?

I would say the most memorable moment in my professional life so far would be receiving the J Clerance Karcher award from SEG. For the success story, I have to go with the time that I understood and applied Spitz's genius idea for removing aliasing from seismic records. Since that time I have been able to use this idea in different contexts to address very challenging problems.

What has been the most difficult challenge in your professional life?

I would say it was the first two years of my Ph.D. program. I was trying to come up with something new, worthy of a Ph.D. dissertation. It is interesting that when I came up with the Multi- Step Autoregressive (MSAR) algorithm I was totally aiming for something different. I was trying to estimate the prediction filter of prediction filters of low frequencies to extend them to high frequencies. During my tests I was getting very good results when the band of low frequencies was wider. Then all of a sudden the MSAR idea popped into my brain. All I needed to do was decimate my operators (prediction filters) at low frequencies to make them valid for high frequencies. I remember that night I couldn't sleep being excited and trying to visualize in my brain how to write the codes for MSAR. It was a great relief to come up with something new. It also helped me a lot for my future work. Now I know that I have to try to understand the problem at hand by testing various ideas and at some point detect a pattern from those tests.

How would you say your career has shaped up so far?

I would say I am satisfied and happy with what I have achieved so far. I am working and doing research on the topics that I enjoy. At the moment I am at a very exciting and important part of my career in geophysics. I need to decide direction for my future career. I am weighing two options: pursuing an academic career or entering into the industrial research environment. Both are very appealing and I hope to figure it out in the very near future.

Mostafa Naghizadeh and Satinder Chopra

You have been working as a post-doc since October of 2009. What are your personal and professional visions that you are working towards?

After being a post-doctoral researcher at CREWES and recently at SAIG I understand the value of spending some time on research after graduating from a Ph.D. program. During the Ph.D. program although many interesting ideas came up I did not always have the time to venture into them. As soon as the pressure of finishing the Ph.D. program was released I was able to investigate ground-roll suppression, time-lapse imaging, multi-component de-noising, and address some challenging issues in interpolation methods.

Most of your work has focused on interpolation methods, or reconstruction of aliased data. Instead of my asking you probing questions, tell us about the body of work you have done, and why you think it is important. Is there anything left in this area for you to achieve?

In interpolation we deal with three main challenges: irregular sampling, spatial aliasing, and complexity of events (curved and discontinuous events). It is very hard to handle all these challenges at once. So I started with pairing them and finding solutions for them. I came up with the Multi-step autoregressive (MSAR) algorithm to handle irregularity and removing alias at once. I introduced the adaptive f-x interpolation to deal with the cases with aliased and curved events but with regular sampling. This pairing of problems provided me with a very good understanding of what kind of transforms and tools are needed to handle them simultaneously. So, I introduced scale and direction guided Curvelet interpolation and Fast Generalized Fourier Interpolation (FGFI) to handle these issues at once. I can't emphasis enough that none of these ideas would be possible without my clear understanding of a classic interpolation paper by Spitz in 1991. And for that I should thank its author Simon Spitz as well as my supervisor Mauricio Sacchi for introducing this paper to me. There is always room for improvement in any discipline or concept, and seismic data reconstruction is no exception. Seismic reconstruction methods still need further improvements in terms of computational time, memory, and resolution.

What in your opinion are some of the tough problems we face in seismic data processing?

In my opinion a challenging problem for seismic data processing in land surveys is to find an optimal way of dealing with static corrections, ground-roll removal, and interpolation. For marine surveys, I think, the important issue is a proper combination of interpolation and multiple removal methods to save costs in data acquisition. Recently, by the momentum that time-lapse surveys are gaining to find optimal ways of obtaining the subsurface difference models, this seems to have become a very interesting research topic. Not to forget the demand for novel processing techniques for simultaneous and blended recordings.

What areas of geophysics fascinate you, but you haven't had the time or the opportunity to put your hands on them?

I would like to work on joint inversion of various geophysical prospecting methods. There are a lot of other geophysical exploration methods which like exploration seismology aim to find an image of the subsurface. Magnetic, gravity, and electromagnetic exploration methods have their own interesting processing aspects. Using all these exploration methods together for a robust inversion of the earth model was always in the back of my mind and I would like to start looking into it soon. I had the chance of working with them separately but I think there is a lot that can be done with some combining.

In your opinion, what is the present scenario of R & D in our industry? Do you think enough is being done to keep our industry going?

I think seismic exploration R & D is well funded and supported, perhaps more so than most of the other branches of geophysical prospecting. Having said that, there is always room for more investment in research to develop new technologies and processing methods. Meanwhile there are a lot of unsolved and hard to handle problems in current industrial processing methods, which with enough attention and resources we might come up with very interesting solutions for.

So, if we acquire a sparse 3D, do you think your interpolation methods can yield a volume that is as good as a volume shot at closer intervals?

Nothing can replace high quality original data but we know how expensive and hard it is to acquire. If we had unlimited resources we could push for the densest possible spatial recording (say deploying one geophone per m2). Now suppose someone came to me and said in an area of 10x10Km, they have gathered a very sparse seismic survey with four geophones on the corners of the area and one shot in the middle. Can you interpolate the data to give us the data with shot spacing 50m and geophone spacing 25m covering all the area? It is an interesting question and you will be surprised that the answer could be both yes and no. It all would depend on what is in the subsurface and what you want to extract from your data.

Interpolation improves the results but is not a pure increase in the amount of information. It is a preparation step to the subsequent processing techniques which without interpolation they would be too complicated to be handled with high confidence. One can ask to somehow integrate the interpolation step inside the wave equation migration, but the challenge is that the optimization procedure in the interpolation method is often non-linear and can't be easily accommodated in an already complicated enough imaging method. So the short answer to your question would be we have very good interpolation methods that can perform well under their own umbrella of assumptions and requirements. If the volume of data and your expectations of the output of the interpolation technique meet these assumptions then interpolation will help you. In a nutshell, consult an Interpolationist (I think I just invented this word) before collecting your data!

Tell us about your decision to come from Iran to Canada and settle down here.

I found Canada's pluralistic and multicultural aspect very appealing. If you want to experience a part of a specific culture from anywhere in the world, say for instance food, you can do that without leaving the premises of this great country. I hope this is the future for the world in 100 years and for me, it is already being realized here in Canada. Since I entered Canada I felt like I fast forwarded my life experience 100 years. Also, here in Canada I respect the standards of human rights, tolerance, democracy, and freedom. I see this not only in the laws but also in the culture and mindset of the population. So, I feel like I am living my life to the fullest extent in Canada. And if you feel fine somewhere why not settle down there? I also met my amazing and lovely wife and have found family here.

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

Geophysics, as it was advertised on an SEG T-shirt, is a multidimensional experience. You can be in touch with the latest discoveries of Physics, Astrophysics, Mathematics, Engineering, and even Biology. You have a wide range of selections to pick your future career. So dive into the vastness of geophysical sciences and explore new horizons. Science is the only way of understanding the reality of our universe and geophysics is one of its finest branches. It is fun and very satisfying to learn what other geophysicists have discovered so far about our little blue dot in the vast universe. It is even more fulfilling when you come up with a new discovery of your own.

Apart from the professional work, what other interests do you have?

I like reading philosophy for the sake of entertainment and exercising my brain, not for answers. For learning facts that I do not specifically study I follow the latest scientific discoveries. I especially like reading about biological sciences such as evolution, abiogenesis, neurosciences, and medicine. To keep the balance between my mental and physical activities I like doing sports. I play soccer for fun and keep participating in soccer tournaments.


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