Contributed by Martin F. Kane
The geophysical career of Bimal K. Bhattacharyya is the record of a man of profound talent who saw fit to couple this talent with prodigious effort for the betterment of our discipline. Although his career in geophysics was a relatively short one, some twenty years, the evidence of this effort is everywhere around us, in his publications, in his students, in his lectures given in all corners of the earth, in our computer applications, and even in his several years of service as an Associate Editor of Geophysics.
The signs of his talent came early, shown first in his early matriculation when he received his high school diploma at the age of 15 and his B.Sc. in mathematics with honors from Calcutta University at the age of 19. He went on to receive an MSc. in radiophysics and electronics in 1951. He did his initial research at the Institute of Nuclear Physics at Calcutta where he worked on the design of the radio-frequency system of the 37" Cyclotron. It was during this time that he began his remarkable publication record, completing seven papers in 30 months. In 1954 he joined the Institute of Technology at Kharagpur and began his first research in solid-earth geophysics, the development of interpretation methods in electromagnetics. He returned to graduate study at Calcutta University in 1955 as both a lecturer and researcher in the Department of Radiophysics and electronics in 1957.
In 1958 he accepted an invitation to do upper atmosphere research in the Radio and Electrical Engineering Division of the National Research Council of Canada. In 1961 he became a member of the Geological Survey of Canada beginning eight years of research there in analysis and application of aeromagnetic data, the subject that was to be the focal point of the remainder of his career in geophysics. He became a professor of geophysics at the University of California, Berkeley, in 1972 where he guided the academic work of several graduate students and continued to expand his theoretical work in potential field methods. It was during this period that his standing as an international authority in potential field theory was firmly established both by his numerous publications and his worldwide journeys to deliver lectures on his research at universities, research institutions, and international meetings.
Bimal joined the U.S. Geological Survey in the summer of 1975 an action strongly advocated by Roland G. Henderson, another Honorary Member of SEG who was retiring from active service with the Survey at that time. Both the range and magnitude of his contribution was extraordinary in the few short years he was with us. He was in many ways the complete geophysicist, a quality especially exemplified by his need to see that his theoretical modeling techniques would lead to practical results. His specific accomplishments, such as the continuation of potential fields to arbitary surfaces, reduction of the magnetic topographic effect, calculation of the Curie isotherm from magnetic data, and establishment of the foundations of satellite magnetometry data reduction and analysis, are readily apparent to us; he was working on the development of the theory of vector magnetometry and on a multibody inversion method for potential field data.
As time passes, however, it has become more apparent to us that it was and is the general thrust and time of his work that is most important. Bimal's development as a scientist was coincident with the emergence of the electronic computer as the plexus of the geophysical industry. He lent his enormous talents to the coupling of this device to the solution of the myriad problems that face us who work in the earth sciences today. Much of what we are doing and will do in the future will be done better because of him. He lives on in his work but his presence is sorely missed.