Misac NabighianThe applied geophysics community has lost a pioneer, an extraordinary scientist, a great teacher and mentor, and an extraordinary human being. Dr. Misac Nabighian passed away on August 8, 2018 from the complications of a heart attack. He is best known as a leading theoretician in electromagnetic and potential-field geophysics where he made many seminal contributions.  He was known for his teachings in applied geophysics, mentoring of many geophysicists, and his extraordinary care for his students, friends, and colleagues.  Through his career, he held leading research positions at Newmont, and held academic appointments at the universities of Berkeley, Columbia, Toronto, Arizona, and Colorado School of Mines. He served on innumerable visiting committees to these and other universities.

Nabighian was born in Bucharest, Romania. He received his B.S. degree in geophysics from the Polytechnic Institute of Petrol and Gas in 1954, where he first developed his mathematical skills. He became in 1957 the assistant to Professor Sabba Stefanescu, one of the leading theoreticians of his generation and whose influence clearly set the tone for Nabighian’s future research in geophysics. They wrote the first theoretical paper on the magnetometric resistivity method, and won the Theoretical Value and Elegance Prize awarded by the Romanian Academy of Sciences for a paper in which they derived an analytic solution for the spiraling magnetic field lines about two inclined long current-carrying wires.

Nabighian immigrated to the United States in 1962. He married Adia Eghiaian 1966 while studying at the Lamont Geological Observatory of Columbia University, where he obtained his doctorate in geophysics in 1967.  Upon graduation, Nabighian joined Newmont in 1967 and where he worked for 31 years until his retirement in 1997. Shortly afterward, he joined the Department of Geophysics at the Colorado School of Mines (CSM) as a Distinguished Senior Scientist, where he taught and pursued a wide variety of research projects. Nabighian retired from CSM in 2017, but remained active in research until his death.

During his years at Newmont, he developed a number of novel theoretical concepts and techniques to interpret gravity, magnetic, DC resistivity, induced polarization, time-domain electromagnetic, borehole, and radiometric data. The magnetometric resistivity method has received his continual attention. His work on the Hilbert transform led to the development of the Analytic Signal technique to quantitatively interpret potential-field data both in 2D (1972, 1974) and 3D (1984). Another important paper “Quasistatic transient response of a conducting half-space: An approximate representation” (1979) provided insight into the behavior of transient electromagnetic fields diffusing into the earth. The impact of this paper has been tremendous and it was selected to be republished in the 1985 classics issue of GEOPHYSICS. In 1984 he served as the editor of a special issue of GEOPHYICS devoted to time-domain electromagnetics and in 1990 he was both editor and contributor to the two SEG volumes “Electromagnetic Methods in Applied Geophysics”, which are still two of the best-selling books published by SEG.

Working as a Distinguished Senior Scientist at CSM, Nabighian taught two high-level courses on applied geophysics, which consistently attracted attendance from both Geophysics and Geology, and were among the highest rated courses. He also presented many special tutorial courses on time-domain EM methods and complex analyses. He co-authored many papers, one of which entitled “Unification of Werner and Euler deconvolutions in 3D via the generalized Hilbert Transform” established a solid theoretical basis for the method of Extended Euler Deconvolution and which was successfully used in the detection of UXO’s using the magnetic method. During the same period, he co-authored a book on “Fundamentals of Gravity Exploration” and a chapter in Treatise of Geophysics on “Magnetic Methods of Exploration – Principles and Algorithms”. In addition, he co-authored many review papers on gravity, magnetic, and electrical methods, which were published during the various milestones of SEG’s existence and some of which were republished in a later classics issue.

Nabighian was Associate Editor of GEOPHYSICS for electrical methods from 1977 to 1981. He was the first recipient of the Gerald Hohmann Award for excellence in electromagnetic research. In 1987 he was awarded Honorary Membership in SEG for his seminal work on electromagnetic methods; in 1994 he was elected Doctor Honoris Causa from the Polytechnic Institute of Bucharest.  In 2016 he was honored by the SEG with the Award of Life Membership.

Nabighian was always exceptionally friendly, warm, and caring; he was truly a scholar and gentleman. He had an enormously positive impact on innumerable geophysicists. As a friend, he gave unreserved advice on life, career, and scientific research. As a scientist, he showed many of us how to achieve simplicity through elegant mathematics, gain insight through physics, and focus on geology through geophysics.

Nabighian was a passionate traveler and food connoisseur.  He visited innumerable places in virtually every corner of the world and often recounted his travels with stories that weaved together food, culture, and nature’s beauty. His love for dark chocolate and espresso was legendary among his students and friends. Who else could have explained the Riemann surface better than Nabighian did with honey baked ham?

Nabighian will be remembered by his colleagues for his unparalleled contributions to electromagnetic and potential-field geophysics, his mathematical rigor, his love of travel and food, and his unreserved mentoring and care for others. He is survived by his wife Aida of Highlands Ranch, their son Edward of San Jose, daughter Diana of Arvada, and three grandchildren of San Jose.