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American National Biography Online Benioff, Victor Hugo (14 Sept. 1899-29 Feb. 1968), seismologist and geophysicist, was born in Los Angeles, California, the son of Simon Benioff, a tailor, and Alfrieda Widerquist. Benioff's father and mother were immigrants, from Russia and Sweden respectively. Benioff attended the public schools of Los Angeles and Long Beach, where he expressed an early interest in science. As a youth, he was particularly interested in astronomy. From 1917 until 1921, while pursuing his undergraduate studies at Pomona College, he spent his summers working as an assistant at the Mount Wilson Observatory in the San Gabriel Mountains above Los Angeles. After receiving his A.B., he accepted a job at the Lick Observatory in Santa Cruz, California, where he worked from 1921 to 1922. Working full time as an astronomer, however, Benioff was troubled by his intolerance for the cold, nocturnal work required to observe the stars. As a result, in 1924 he secured a position with the Seismological Laboratory in Pasadena, California, one of the leading centers of the emerging study of seismology, then run by the Carnegie Institution of Washington, D.C. As an assistant physicist at the lab, Benioff was assigned the task of developing a system to drive seismological recording drums. He soon proved himself an able instrument builder, developing a new impulse motor that could measure the arrival times of seismic waves to an accuracy of .1 second. This instrument was the first of many Benioff developed during the course of a career that transformed seismology from a mostly qualitative study of the effects of earthquakes on man-made structures into a detailed, quantitative science focused on the recording and analysis of seismic wave energy. As a result of his work at the lab, Benioff decided to pursue seismology as a career. He began graduate study in seismology at the California Institute of Technology and in 1935 received a Ph.D. Not satisfied with his early instrumental improvements, Benioff continued to strive for ways to further enhance the precision and sensitivity of seismographs. In 1931 he finished work on a variable-reluctance seismometer that allowed for extremely high magnification of small seismic movements. This feature enabled the instrument to measure both small local earthquakes and larger, distant ones. Benioff next worked on perfecting a linear strain seismograph. By responding to ground motions in a different manner from that of the traditional pendulum seismometer, Benioff's instrument allowed for the detection of different types of seismic waves, especially those generated by deep-focus earthquakes. Benioff's instruments soon were incorporated into a network of linked recording instruments throughout southern California that gave researchers at the Pasadena laboratory the ability to precisely pinpoint and gauge the relative magnitude of local earthquakes. This network contributed to many new insights into earthquake mechanics and led directly to the development, by Benioff's Caltech colleagues Charles Richter and Beno Gutenberg, of what came to be known as "the Richter scale" in 1935. This scale provided a method of ranking the intensity of different ground motions based on a logarithmic scheme, generating a single number that could represent the relative size of earthquakes. In 1937 the Pasadena Seismological Lab was officially joined to the California Institute of Technology; Benioff was appointed to the position of assistant professor of seismology at Caltech and was soon afterward raised to associate professor. Although a member of the regular faculty, Benioff preferred his work on instruments to teaching and had relatively little formal contact with students. Researchers and graduate students sought him out, however, for his insight into the particular problems of instrumentation and the detection of seismic waves. During the Second World War, Benioff participated in a program for improving radar and sonar detection for the Submarine Signal Corporation, and during the 1950s he took part in a program for the detection of underground nuclear explosions. During the 1940s Benioff's interests in the transmission of waves also led him to develop electronic amplifiers for the violin and cello. These "seismographic fiddles" had the same design as their conventional counterparts, except that the wooden resonance chambers were replaced by a small, aluminum container beneath the strings. Within this compartment, the musical vibrations caused a crystal to generate electrical current, which was then amplified. Benioff's instruments were hailed for producing tones of outstanding clarity and depth. From 1946 to 1962 Benioff worked as a consultant with the Baldwin Piano Company and helped them to develop electronic instruments, including a violin and a piano, based on the same principles. In his home, Benioff constructed an elaborate system of recording equipment and built a superb library of recordings. He also developed a means whereby the seismic waves of earthquakes could be played back on an audio system, allowing researchers to actually "hear" the sound of earthquakes. Benioff also won acclaim for his contribution to a prediction made in 1949 by Beno Gutenberg, director of the Caltech seismological lab, that the Pacific Coast region was due for either a large earthquake or a series of small tremors. This prediction was based on measurements made by Benioff revealing that the subsurface strain in the central California region was building. In 1950 a series of tremors shook the lower Imperial Valley, and in 1952 a major quake took place in the region. Later in his career Benioff became interested in the study of microseismic waves, the slight shaking of the earth's crust that goes on continually. He also worked on magnetic micropulsations, which are small geomagnetic fluctuations in the earth's magnetic field. These researches led to his work on detecting the free vibrations of the earth. Benioff's broad interests and contributions to seismology won him widespread recognition in the field. In 1950 he became a full professor at Caltech, and in 1953 he was elected to the National Academy of Sciences. He also served as the president of the Seismological Association of America. In 1964 Benioff became professor emeritus at Caltech but continued his research and consulting work. He served as adviser to both the government and private industry on issues of the seismic safety of nuclear power plants. During his career he published many significant papers on seismography, microseisms, and earthquake dynamics. Benioff was married twice. His first marriage, to Alice Silverman, in 1928 produced three children. They divorced in 1953. That same year he married Mildred Lent, with whom he had one child. Benioff was a great lover of nature and the outdoors. Following his retirement, he moved to Cape Mendocino in northern California to enjoy the beauty of the natural environment of that area. While there, he died suddenly of a heart attack. His contributions to seismology, especially in the development of seismic instruments, made him one of the founding figures of the modern study of earthquakes. Bibliography Biographical information on Benioff can be found in the historical files and in several oral history interviews in the archives at the California Institute of Technology. Among Benioff's most significant scientific papers were his descriptions of his new seismographs published during the 1930s in the Bulletin of the Seismological Society of America. A good summary of these developments is Benioff's "Seismological Instruments Developed at the C.I.T.," Engineering and Science 11 (Feb. 1948): 24-25, 31. A biography of Benioff by Frank Press is in the National Academy of Sciences, Biographical Memoirs 43 (1973): 27-40. The best survey to date on the development of seismology in America is Judy Goodstein, "Waves in the Earth: Seismology Comes to Southern California," Historical Studies in the Physical Sciences 14 (1984): 201-30. An obituary is in the New York Times, 2 Mar. 1968. David A. Valone From American National Biography, published by Oxford University Press, Inc., copyright 2000 American Council of Learned Societies. Further information is available at http://www.anb.org.