In Memory of Lev Vinnik

Lev Vinnik

(March 29, 1935 - September 27, 2023)

On 27 September 2023, Lev Pavlovich Vinnik - Doctor of Physical and Mathematical Sciences, Chief Scientist of the O.Yu. Schmidt Institute of Physics of the Earth RAS, outstanding scientist-geophysicist, seismologist of world fame - died in the 89th year of his life.

L.P. Vinnik was born in Smolensk on 29 March 1935. In 1957 he graduated from the Faculty of Geology of the Lomonosov Moscow State University as a geologist-geophysicist. In 1957-1959 he spent the winter in Antarctica as a member of the 3rd Continental Antarctic Expedition. In 1959 he joined the Institute of Physics of the Earth. Initially, he worked in the field of seismic detection of nuclear explosions and, after defending his PhD thesis in 1966, in the field of research of the internal structure of the Earth. For a long time he was the head of the Laboratory of Seismological Research and the Department of the Internal Structure of the Earth.

L.P. Vinnik is known for the highest skills in the analysis of observations. He was a pioneer in the development of methods used worldwide to study the structure of the Earth's interior: the receiver function method and the seismic anisotropy measurement method (SKS method).The method of receiving functions makes it possible to determine with high accuracy the relief of deep seismic boundaries, which depends on the temperature and material composition of the subsurface. Seismic anisotropy is determined by the ordered orientation of mineral grains acquired during plastic flow and is an indicator of these flows. Together with other studies, this work formed the science of seismic tomography, which in recent decades has revealed the complex structure of the Earth.

L.P. Vinnik did not limit himself to the development of new methods of seismological data analysis, but also carried out a practical analysis of a huge volume of observations. In particular, he showed that the currents on the continents diagnosed by the SKS method were in some cases related to continental drift. He studied the stratification of the Earth's interior from the crust to the surface of the liquid core and found partial melting in layers at depths of the order of several hundred kilometers, where these phenomena were previously unknown. He found evidence of seismic anisotropy just above the core boundary. For a better understanding of geological processes, L.P. Vinnik carried out detailed studies of the structure of the Earth's upper mantle to depths of 200-300 km for a number of regions of continents (Tien Shan, Fennoscandia, Greenland, Indian Shield, Himalayas, Tibet, etc.) and oceanic islands. He provided new insights into the structure of the lithosphere of the Indian subcontinent, showing that the Archean mantle keel of the Indian Shield has been reworked by more recent processes, but the part on which the western Himalayas, Ladakh and western Tibet are built has been preserved. In the depth range from the free surface to the lower mantle, the Azores and Cape Verde hotspots have been studied. New insights into the nature of the 520-kilometre seismic boundary were obtained, and it was shown that this boundary represents the footwall of a low-velocity layer in the mantle transition zone.

Using numerical modelling, he discovered the flawed nature of many papers in which the analysis of the anisotropic properties of the lower mantle at the core boundary was based on the splitting of diffracted transverse waves. The method of studying azimuthal anisotropy as a function of depth has been improved and its practical application has begun. In the study of the Kalahari craton in South Africa, it was shown that at a depth of 160 km, the frozen anisotropy inherited from the Precambrian is replaced by active anisotropy associated with modern mantle flow. Large changes in the properties of mantle xenoliths transported from depths greater than 160 km were previously known, but the cause of these changes was unknown.

In the mid-1960s, he worked extensively on the study of seismic noise (microseisms) and discovered that in quiet intracontinental regions of the USSR, the noise consisted of longitudinal waves with almost vertical rays. Previously, microseisms were thought to be exclusively surface waves.

L.P. Vinnik is author of more than 200 publications.

He has carried out research at the NORSAR Seismic Data Centre (Norway), the Central Seismological Observatory of the Federal Republic of Germany (Erlangen), the Paris Institute of Physics of the Earth, the University of California at Berkeley, the Earthquake Research Institute (Tokyo), Institute of Geophysics, University of Johannesburg (South Africa), the Centre for Geosciences in Potsdam (Germany), the Institute of Geophysics, University of Oulu (Finland), the University of Lisbon, the Department of Geophysics, University of Copenhagen, two universities in Turkey and the National Geophysical Institute of India (Hyderabad). From 2002 to 2010 he lectured on direct and inverse problems in seismology at the International School of the Institute of Theoretical Physics in Trieste (Italy). He has participated in the work of the International Geodynamic Project and the Inter-Union Commission on Lithosphere. In 1993-1998 he co-chaired the project "Dynamics of the continental upper mantle: from seismic anisotropy to mountain structure" of the International Programme "Lithosphere". He has been invited as a panel member for the European Research Council (ERC, Brussels) grant competitions.

In 1993 L.P. Vinnik was elected a member of the European Academy (Academia Europaea), in 1994 - a Fellow of the American Geophysical Union (Fellows are elected annually from one in a thousand members of the Union). In 1995 he had the honour of delivering the Gutenberg Lecture at a meeting of the Union. He has been awarded the Humboldt Prize (Humboldt Foundation, Germany, 1991), the B.B. Golitsyn Prize (Russian Academy of Sciences, 1997), and the B. Gutenberg Medal, awarded in 2004 by the European Union of Earth Sciences for "pioneering work in seismology and the introduction of widely used methods of analysis". The Seismological Society of America (SSA) awarded Lev Pavlovich Vinnik the 2016 Harry Fielding Reid Medal, the Society's highest honour, for outstanding contributions to world seismology.

A talented, intelligent and caring person has left us. The bright memory of Lev Pavlovich Vinnik will forever remain in our hearts.

Prof. Alexey Zavyalov,

Titular member of Russia in ESC