V.V. Metallova.

Boris Mikhailovich Yanovsky

On November 15, 1994 the 100th anniversary of Distinguished Fellow of Russian Federation in Science and Technology, full professor of Leningrad University B. M. Yanovsky was celebrated. B. M. Yanovsky was born in the village of Kuvshinovo near Vologda in the family of a local medical officer. His father died early, at 36, and his mother had to raise two young sons aged 8 and 6. Despite the financial difficulties, she was able to provide for the secondary education for both children. After graduation from a gymnasium (main form of secondary education in Tsar’s Russia) in 1912, Boris Mikhailovich left for St. Petersburg and entered the department of physics and mathematics at St. Petersburg  University. Being the elder son, he could not count for the financial help from his family, and so had to teach private lessons to support himself during his studies. After graduating in 1916 Boris Mikhailovich was offered a teaching position at the University, but soon he was conscripted to the military. Having graduated in 1918 from the short-term Navy school he was assigned to Pavlovo magnetic observatory, where his duty was to organize the magnetic survey of Ladoga and Onego Lakes. This was the start of the half-centennial career of B. M. Yanovsky in geomagnetism and magnetometry, which he pursued in Mendeleev Institute of Metrology (VNIIM) and Leningrad University.

 

In 1919-1926 B. M. Yanovsky was one of the most active participants of the investigation of Kursk Magnetic Anomaly led by Academician P. P. Lazarev. He carried out the mathematical interpretation of the magnetic survey results. This allowed to trace the origin of the anomalous magnetic field in the vast region near Kursk to magnetized bodies located at 50 to 400 m depths. Drilling has confirmed the predictions of geophysicists, having discovered ferrigeneous  quartzites at these depths. Studies of the geomagnetic field led by B. M. Yanovsky were extended in 1930-1938 to include Western Urals, left bank of Volga (Second Baku), and Cisbaikalia. Boris Mikhailovich developed a number of methods of quantitative interpretation of magnetic survey results, allowing to determine depths of anomaly sources. Following the magnetic survey, elevations of the crystalline basement, to which oil fields are related, were found in the Second Baku area. In all, studies at Kursk Anomaly and in Western Urals have shown the prospects of magnetic surveying in ore exploration and structural geology.

 

During the same time, after having joined VNIIM in 1926, B. M. Yanovsky actively works in magnetometry, particularly as applied to weakly magnetic materials. He also carries out studies of new materials for permanent magnets, which were the necessary part of magnetometers at this time. B. M. Yanovsky also starts studies into the magnetic properties of rocks, which he pursued during the rest of his life.

 

In 1934 Boris Mikhailovich was invited to the faculty of physics of Leningrad University to give lectures on magnetic measurements and to organize a laboratory to study rock magnetism. From this time his life was closely connected with the University. In 1939, under the guidance of Boris Mikhailovich, graduate student T. N. Roze had completed a study of thermoremanent magnetization of rocks, one of the pioneering works on this subject in the world. Also in the 1930ies B. M. Yanovsky has led studies into using natural variations of the geomagnetic field for the determination of rock magnetic properties in situ and for separation of anomalies due to remanent and induced magnetization respectively. For this purpose, magnetic variations were recorded in an anomalous (in the Kursk Anomaly area) and in normal geomagnetic field, using new magnetographs designed by Boris Mikhailovich.

 

In 1944, after returning of the University to Leningrad from the evacuation B. M. Yanovsky has become head of the Chair of Earth’s Crust Physics at the faculty of physics, later renamed to the Chair of Physics of the Earth. It must be noted that the chair was literally rebuild from scratch. By this time, it lost many of its former members to war and to Stalinist repressions. In the geomagnetic laboratory, studies of the magnetic properties of rocks were continued; in particular, origins of the reversed natural remanent magnetization of rocks from Angaro-Ilim negative magnetic anomaly area.

 

In the early 1950ies, a new branch of geomagnetism, paleomagnetism, or study of the history of the past geomagnetic field, receives a powerful boost. Paleomagnetism not only made revolutionary changes in the ideas on the magnetism of the Earth, but also was the most instrumental in the development of a new paradigm in Earth science on the whole – global plate tectonics.

 

Boris Mikhailovich, being always aware of the most important developments in geophysics, lends all his support to paleomagnetic studies in the USSR. The growing number of these studies in 1950 – 1960ies required their coordination, and in 1958 B. M. Yanovsky serves as one of organizers of the Commission on Main Geomagnetic Field and Paleomagnetism at the Earth Science Department of the Academy of Science of the USSR, later reformed into the Scientific Council on Geomagnetism  at the Presidium of the Academy of Science. From the beginning of this Commission  until the end of his days B. M. Yanovsky was its chairman. Commission was the most active in organizing national scientific meetings and supporting new paleomagnetic laboratories countrywide. At this time, geomagnetic laboratory at the Chair of Earth Physics carries out studies of physical foundations of paleomagnetism, magnetization of Siberian traps, paleomagnetism of Devonian sedimentary rocks. Studies of physical processes of magnetization acquisition in rocks are continued in the laboratory until present time.

 

In 1950 – 1960ies B. M. Yanovsky has led a series of important projects in metrology related to the introduction of SI into scientific practice and the necessity to revise the definitions of magnetic and electrical standards. This logically led to an idea of developing metrological standards based on the intra-atomic processes. For this purpose fundamental physical constants had to be determined with the highest possible precision. Boris Mikhailovich therefore leads the VNIIM works on the determination of the gyromagnetic ratio of a proton. Results of this work received an approval of the Committee on electrical measurements of Bureau International des Mesures et Poids. Based on these results, Boris Mikhailovich has proposed new standards for units of the intensity of magnetic field and of electrical current. Later he initiated the work on precise determination of Breit-Rabi constants, necessary for measurements of weak magnetic fields by the optical pumping method. Worth noting, that in the same time a first instrument for the determination of components of the geomagnetic field by the proton resonance method was built under the leadership of B. M. Yanovsky.

 

Boris Mikhailovich’s interest in geophysics was not limited to geomagnetism sensu stricto. Heading the Earth Physics chair for nearly 25 years, he initiated new studies in various aspects of the Earth science. On his suggestion, the magnetotelluric method to study the Earth’s crust conductivity was introduced into practice, and new magnetometers for recording short-period variations of the geomagnetic field were designed in support of the magnetotelluric studies.

 

Boris Mikhailovich stimulated studies of the variable geomagnetic field, which later developed into the scientific discipline of magnetospheric physics. He paid some attention to the developments in seismology and geoelectrics.

 

Alongside with the first-class research, B. M. Yanovsky was a noted educator. His disciples worked in various branches of geophysics in the USSR and abroad; over twenty of his graduate students received Candidate of Science degrees, several became Doctors of Science.

 

Boris Mikhailovich also contributed significantly to science management. As noted above, he was one of the founders of the Commission on main geomagnetic field and paleomagnetism; he was also a member of the Soviet committee for the International Geophysical Year (1958).  For may years Boris Mikhailovich was an active member of the editorial board of Izvestia of Academy of Science USSR, ser. Geophys., participated in IAGA assemblies, other international and national scientific meetings, was the chairman of the seminar on magnetometric instrumentation.

 

Scientific legacy of Boris Mikhailovich includes over 100 papers, nine monographs and textbooks. His magnum opus – textbook “Terrestrial Magnetism” – was published in three intravital editions and became a main textbook on the subject for many generations of geophysicists in the USSR. It was translated into several languages. Fourth, posthumous edition was prepared by disciples and colleagues of Boris Mikhailovich and published by Leningrad University Press in 1978.

 

Achievements of Boris Mikhailovich in science and education received high merits. In 1965 he was awarded the title of Distinguished Fellow of Russian Federation in Science and Technology. He was awarded the Order of Lenin, the Order of Merit, and several medals. His name is given to rock outcrops in Riser-Larsen Peninsula, Antarctica (69°15¢S, 34°25¢E).

 

Boris Mikhailovich was a man of outstanding personality. Always benevolent and easy in communication, he had welcome everybody addressing to him with great interest and desire to be of assistance, was able to joy sincerely the successes of others. VNIIM archives keep a curious document dated 1950, when Boris Mikhailovich was the VNIIM director. There may not be a better evidence of his personality. This is a merit rating, in which a very high evaluation of the activities of the director is accompanied by the following passage: «… has a party admonition for allowing personnel mismanagement and not taking measures for liberating the institute of socially alien and politically unsound persons».

 

Interests of Boris Mikhailovich were extremely wide. He was an excellent connoisseur of music and a passionate collector of music records. Boris Mikhailovich loved poetry and literature, excellently knew Russian and world history, architecture of Leningrad. Until the end of his days he retained great interest to life.

 

Boris Mikhailovich Yanovsky died on December 12, 1967.

 

Disciples of Boris Mikhailovich remember with gratitude their Teacher, who wholeheartedly shared with them his knowledge and experience, taught them the difficult science of human communication. In memories of those who knew Boris Mikhailovich, he always will be not only an outstanding geophysicist and metrologist, but also an outstanding man, true Russian intelligent in the highest meaning of this word.