Leon Knopoff
Leon Knopoff ( born July 1, 1925 in Los Angeles, † January 20, 2011 in Sherman Oaks ) was an American geophysicist. He was considered one of the fathers of theoretical seismology.
Biography
After schooling, he studied electrical engineering at the California Institute of Technology ( CALTECH ) and graduated in 1944 from. He then completed a post-graduate studies in physics at the CALTECH and finished this in 1949 with a doctoral thesis.
He then spent two years at Miami University and then became a research associate at the University of California, Los Angeles ( UCLA), in 1957 there was an associate professor and in 1959 was awarded a full professorship in geophysics. In 1956 he designed before a first representation theorem for complete seismic wave equation and also presented important work in the field of diffraction of seismic waves before, such as in relation to the earth's core.
In 1961 he was appointed professor of physics there also. In 1964 he published with Robert Burridge, the representation theorem of Burridge and Knopoff, which forms an important basis of theoretical seismology. In 1967, he created the basis for the computer simulation of seismicity to geologic faults with the Burridge - Knopoff model. In this model, the points are simulated on the rejection by the masses, which are held by spring forces and communicate with each other and are subject to a frictional force. He thus simulated earthquake on both the computer and in physical models ( Slider Model). One result of the investigations was that earthquakes tend to occur in clusters.
Between 1972 and 1986 he also served as Associate Director of the Institute of Geophysics and Planetarphysik ( Institute of Geophysics and Planetary Physics, IGPP ) at UCLA. In 1980 he described a universal statistical power law ( ie, a fractal distribution) for the spatial allocation of earthquakes that have consequences for the geometry of earthquakes on faults. He also studied in detail the statistics of the temporal sequence of foreshocks larger earthquake to develop with the aim of a prediction method. However Knopoff also demonstrated that most small earthquakes were not Foreshocks that preceded large earthquakes, but showing signs of stress relief.
He also examined the correlation between earth tides and earthquakes. In 1964 he came to the conclusion that no relationship existed. In 1983 he examined the problem again with the astronomer Steven Kilston, this time at the regional level in California ( due to the particular north-south orientation of the San Andreas fault ) and only for strong quake and found correlations ( for example, the quake occurred mostly at full - and new moon, and at sunrise and sunset). They said in their Nature article stronger quake of 1987 in the Imperial Valley in California before, and two also entered.
He also dealt with the determination of the velocity of seismic waves, measurements of earth tides at the South Pole, Age determination of ceramics with thermoluminescence and musicological issues ( he studied from 1960 at the Institute of Ethnomusicology at UCLA, published by William Hutchinson work on psycho- physical aspects of music and played himself piano and harpsichord).
Knopoff published over 350 scientific papers and had 38 doctoral students at UCLA.
For his work he received the 1978 Emil Wiechert Medal of the German Geophysical Society, and in 1979 the Gold Medal of the Royal Astronomical Society. In 1990 he received the Medal of the Seismological Society of America. 1972 to 1974 he was in the Earthquake Council of the Governor of California.
He was a member of the National Academy of Sciences (1963 ), the American Association for the Advancement of Science, the American Philosophical Society and the American Academy of Arts and Sciences (1965). He was an honorary doctorate from the University of Strasbourg (2004) and Honorary Professor at the Institute of Geophysics, China Earthquake Administration ( 2004). He visited China since the 1970s.
Even after his retirement Knopoff was more active and, among other author in the journal "Nature". 1985 to 1990 he was in the editorial board of the journal Science.
A professor at UCLA is named after him and his wife Joanne VC Knopoff, donated by two in 2001 by a donation of $ 500,000 to the university.
Publications
- Fred Schwab, Leon Knopoff: Surface waves on multilayered anelastic media, Bulletin of the Seismological Society of America, 1971
- W. Gary Ernst, DT Griggs, Leon Knopoff and LB Slichter: William Walden Rubey, University of California: In Memoriam, 1976