Luis Alonso Gallardo
Biography 2012 (with a 2019 update) 
Luis A. Gallardo received an M.S. (1997) in applied geophysics from CICESE, a Ph.D. (2005) in environmental science from Lancaster University, and held the Goodeve Lectureship (2009–2011) at the University of Western Australia. He is a titular researcher in the Department of Applied Geophysics at CICESE, Mexico; a national scientist from the National Council of Science and Technology, Mexico; and an adjunct scientist of the Centre for Exploration Targeting at the University of Western Australia. His research interests include geophysical inverse theory and the joint inversion of gravity, electromagnetic, and seismic data. He has worked on geophysical imaging for mineral and petroleum exploration in Western Australia, Western Turkey, Southeast Brazil, and West Africa. He has also worked on near surface imaging projects for environmental and geotechnical applications.
Max A. Meju and Luis Alonso Gallardo received the 2019 SEG Reginald Fessenden Award for their innovations in creating the field of multi-physics imaging in the fields of ground water hydrology, near surface geophysics, electromagnetic, and the field of medicine.
The 2019 SEG Reginald Fessenden Award 
by Jie Zhang
Luis Alonso Gallardo and Maxwell A. Meju are recognized by the international hydrogeophysics community and the oil and gas industry as the developers of the current method of cross-gradient joint inversion. The cross-gradient joint-inversion method made it possible to relate what were physically unrelated fields, opening a new field of multiphysics imaging used widely in academia and industry. The method has had substantial impact on geophysical structure, electromagnetics, near-surface analysis, engineering and hydrogeology applications, and the field of medicine. The cross-gradient joint-inversion technology is directly relevant to applied geophysics and is being commercialized by service companies such as CGG, GeoTomo, and Schlumberger-WesternGeco and majors such as Shell, ExxonMobil, and Saudi Aramco. As an example of impact, today SEG workshops and AGU conferences have dedicated sessions on this topic, and a related book was published in April 2016 by AGU Books and Wiley & Sons Inc. There are more than 200 papers by other researchers who are now using this groundbreaking approach, and the contribution of Gallardo and Meju to applied geophysics is recognized in all parts of the world.
Biography Citation of the 2019 SEG Reginald Fessenden Award
Luis Alonso Gallardo and Maxwell Azuka Meju are well known for their invention in 2003 of the cross-gradients approach that allows joint inversion of multiple geophysical data sets. The emergence of the method led to a new era in geophysical imaging — true joint inversion of different geophysical data sets as opposed to integrated or sequential inversion. Their inversion created a new field for both academia and industry. A large number of publications followed, and the geophysical industry commercialized the method for routine services. Clearly, cross-gradient joint inversion is one of the few modern inventions that remarkably changed geophysical imaging and helped improve our understanding of the earth. The invention also has been adopted worldwide in medical imaging, hydrology, environmental engineering, and structural geologic imaging.
Luis currently works as a senior titular scientist and Earth Sciences Division director at Centro de Investigación Científica y de Educación Superior de Ensenada, Mexico. Max currently works as a principal quantitative geophysicist at Petronas, Malaysia. The two made this invention when they worked at Lancaster University, Lancaster, UK, where Max was a senior associate professor and Luis was a PhD student under Max's supervision. They introduced the concept of the cross-gradients method in the joint 2D dc resistivity and seismic inversion in 2003 and 2004. Calculating the cross gradients of two different geophysical properties (e.g., resistivity and seismic velocity) and minimizing the cross gradients in the inversion objective function implies that any spatial changes occurring in both resistivity and velocity must point to the same or the opposite direction irrespective of the amplitude. The approach fundamentally solved the problem of constraining different geophysical properties mutually in a simultaneous fashion regardless of their parameter amplitudes.
Since their initial publication of the novel approach, Luis and Max have published 20 additional papers on joint inversion of seismic, electromagnetic, resistivity, magnetotelluric, gravity, magnetic, etc. Their 22 papers have been cited more than 800 times. More than 260 technical papers by other researchers worldwide have been published following their approach to solve various joint geophysical imaging problems. An American Geophysical Union (AGU) session dedicated to this subdiscipline was convened in 2010, and related workshops on joint inversion were convened on 22 October 2010 by the SEG Research Committee (see review in The Leading Edge, May 2011, pp. 568–571) and 4–6 October 2016 (SEG Dubai Multiphysics workshop). A graduate-level textbook dedicated to this topic was published in March 2016 by AGU Books and John Wiley & Sons Inc. (Integrated Imaging of the Earth, M. Moorkamp, P. Lelievre, N. Linde, and A. Khan, eds.).
Energy-related companies such as Schlumberger, Geosystem, WesternGeco, CGG, GeoTomo, Saudi Aramco, Shell, SINTEF Petroleum, Statoil, Petronas, Petrobras, and many others have adopted this approach for improved decision making in exploration and production applications as can be confirmed from recent SEG and European Association of Geoscientists and Engineers technical workshop proceedings. In a recent effort, Max is collaborating with CGG Multi-Physics Imaging to extend the cross-gradients approach to solving seismic image-guided 3D inversion of marine controlled-source electromagnetic and magnetotelluric data. Luis is actively expanding to new joint-inversion methodologies and applying joint geophysical inversion to several major projects involved in monitoring geophysical properties in geothermal fields.
After his PhD study, Luis returned to Mexico and continued his academic research efforts. He also held the Goodeve Lectureship at the University of Western Australia from 2009 to 2011. He received the National Researcher Award in multiple years, and he was nominated by SEG as Geophysics Outstanding Reviewer in 2011. Max left Lancaster University and joined Petronas in 2008. He was awarded the British Geophysical Association's Bullerwell Lecture award in 1996 for outstanding leadership in geophysical inversion theory and practice and for demystifying the mathematics of geophysics. He also received the 2002 Gerald W. Hohmann Award, a highly regarded honor given to an individual or group who has developed and deployed electrical or electromagnetic geophysics as a tool to achieve significant socioeconomic progress. Now, both Luis and Max are recognized with the SEG Reginald Fessenden Award. Their significant accomplishments in cross-gradient joint inversion will be lasting contributions to our science and technology.
Biography 2007 
Luis A. Gallardo received an M.Sc. (1997) from Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Mexico, and a Ph.D. in environmental sciences from Lancaster University, U.K. Since then, he has been a researcher in the applied geophysics department at CICESE. Gallardo’s research focuses on development of joint inversion methodologies for quantitative integration of multiple geophysical data such as gravity, magnetic, EM, and seismic data and analysis of its implications in subsurface characterization.