Keith Edward Bullen

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Keith Edward Bullen (born June 29, 1906 in Auckland , † September 23, 1976 ibid) was a New Zealand mathematician , geophysicist and seismologist .

Life

Bullen enjoyed his school and student training not far from his hometown Auckland. In 1922 he graduated from the Auckland Grammar School with an honors in mathematics and science along with admission to the university. In the following years he graduated in the field of mathematics, in which he also received other awards. In 1928 he became a lecturer in mathematics at Auckland University College .

Bullen left the university temporarily in 1931 to do his PhD at St John's College at Cambridge University , but then returned to Auckland to resume teaching. In 1940 he moved to Australia, where he initially worked as a lecturer at the University of Melbourne . Five years later he became professor of applied mathematics at the University of Sydney , where he stayed until his retirement in 1971.

Keith Bullen married Florence Mary Pressley in 1935. They had two children together, John (* 1936 in Auckland) and Anne (* 1943 in Melbourne). Bulls died of a heart attack at the age of 70.

Research work

During his years in Cambridge, Bullen was a student of Harold Jeffreys , who at the time was working on a revision of the travel times of earthquake waves , which at that time still had errors of up to 20 seconds. One of the first publications by Bullen (with Jeffreys) was a Nature article on the corrections to the P-wave delay times. After returning to New Zealand, Bullen kept in close contact with Jeffreys and completed his doctoral thesis in Auckland.

In 1940 both published the so-called Jeffreys-Bullen Tables - an overview of the running times for different seismogram phases, which over several decades formed the basis for understanding the inner structure of the earth. This was the first time that a defined layer model of the earth existed.

However, Bullen subsequently published further studies and tables of his own on further reflected earthquake waves. Later work dealt with the structure of the earth, calculations of distances in seismology and the change in density in the earth's interior with increasing depth. At the latest with the publication of the latter topic in the 1950s, Bullen gained worldwide recognition and became one of the leading geophysicists of his time.

Bullen refined the earth model further and came to the conclusion that the earth's mantle and core must be chemically different. He further postulated the occurrence of an extremely large density gradient in the lowest 200 km of the earth's mantle, the zone that is now known as the D "layer . Other publications by Bullen also deal with the state of the terrestrial planets. The density distribution Bullens' main field of activity remained in the earth, which he discussed in detail in his last book, The Earth's Density , published in 1975 .

Bullens life's work comprises around 290 publications, some of which have had a decisive influence on geophysics. His international recognition was also expressed in numerous offices: He was President of the International Association of Seismology and Physics of the Earth's Interior and Vice-President of the International Union of Geodesy and Geophysics and of the International Scientific Committee for Antarctic Research as well as other working groups and committees who dealt with geophysics and seismology.

The energy Bullen put into his work has been described as phenomenal by his former PhD supervisor Harold Jeffreys. At congresses and meetings he was always willing to talk to interested parties regardless of age. Keith Bullens achievements and merits have been recognized with a variety of honors and awards.

Fonts (selection)

  • Tables for converting geographic into geocentric angular distances . Isle of Wight 1938
  • An introduction to the theory of mechanics . Sydney 1949
  • An introduction to the theory of seismology . Cambridge 1952
  • Seismology . London 1954
  • The interior of the earth , Scientific American, September 1955
  • The Earth's density . London 1975

Awards and honorary memberships (selection)

literature

Web links

personal data
SURNAME Cops, Keith Edward
BRIEF DESCRIPTION New Zealand seismologist, mathematician and geophysicist
DATE OF BIRTH June 29, 1906
PLACE OF BIRTH Auckland , New Zealand
DATE OF DEATH 23rd September 1976
Place of death Auckland , New Zealand