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Caltech's Seismological Laboratory—informally known as the Seismo Lab—has a long and distinguished history, reflecting both its contributions to science and its service to the public. The Seismo Lab is one of the world's most renowned centers for geophysical research.
The Seismo Lab was established by Harry Wood in 1921 under the auspices of the Carnegie Institution of Washington. In the early 1920s, Wood and John Anderson developed the Wood-Anderson torsion seismometer that became the standard for local earthquake recording. Hundreds of these instruments are still in regular use today.
In 1926, the Laboratory began cooperative operations with the new geology division of Caltech and embarked on a project to install a network of seismographs around Southern California. By 1932, six instruments were in place and the routine publication of a station bulletin had begun.
Charles Richter, originally trained as a theoretical geophysicist, joined the staff of the Seismo Lab in 1927. Beno Gutenberg, a renowned German geophysicist, joined the geology division of Caltech in 1930, and became the Lab's director in 1946.
In the early 1930s, two Caltech scientists—physicist Charles Richter and mathematician Beno Gutenberg—played a pivotal role in developing seismology into an international science of earthquake study and detection.
Responsibility for the Seismo Lab, its programs, and most of its personnel was transferred to Caltech in 1937. Gutenberg and his colleagues—Hugo Benioff, John Buwalda, Richter, and others—led the Seismological Laboratory to worldwide prominence in the study of local earthquakes and, equally important, in the use of teleseismic recordings to study the Earth’s deep interior.
Buwalda came to Caltech in 1926 to organize the Division of Geological
Sciences. He assembled the staff, worked out the instruction and research
programs in geology, paleontology, and geophysics, and supervised the
design and construction of the Charles Arms and Seeley W. Mudd laboratories
on campus. In addition to teaching, he had a distinguished career as a
Frank Press, who later was to become the director of the Office of Science and Technology Policy in Washington as well as president of the National Academy of Sciences, became the Seismo Lab’s director in 1957. Press was largely responsible for developing innovative quantitative approaches to seismology and in making the laboratory heavily computer-based.
In 1974, during the directorship of Don Anderson, the Seismo Lab moved from its original location at Kresge to its current location on campus in South Mudd. By this time, the lab’s seismic network included 30 stations. At the same time, the Seismo Lab and the United States Geological Survey (USGS) began a cooperative program that developed into the Southern California Seismic Network (SCSN).
In 1977 Dr. Hiroo Kanamori developed the Moment Magnitude scale, which replaced the Richter scale for measuring earthquakes M5.0 and larger. Using the improved method, scientists were able to obtain more precise measurements of the energy of large earthquakes that occurred in the past, such as the 1960 Chilean earthquake and the 1964 Alaskan earthquake, as well as a better means of studying and analyzing seismic events when they occur.
Under Hiroo Kanamori's leadership, from 1990 to 1998, the Southern California Seismic Network continued to expand and improve its instrumentation, particularly with broad-band seismographs. Kanamori himself is an international leader in the understanding of the mechanics of large earthquakes and their impact on worldwide mountain-building processes. Over the years, this has continued to be a major emphasis at the Laboratory. Most recently Hiroo Kanamori has developed an algorithm for a new earthquake early warning system, which would allow several seconds of warning that an earthquake has occurred and intense shaking is imminent.
Don Helmberger took over the reins of the Laboratory from 1998 to 2003, and he and his students pioneered in sophisticated quantitative waveform modeling that greatly improved the analysis of earthquake rupture dynamics and strong ground motions and their engineering consequences. Continued cooperation with the U.S. geological Survey led to an ever-more-sophisticated seismographic network, both for recording local events and distant earthquakes.
Jeroen Tromp, Director of the Seismological Laboratory from 2003 to 2008, pioneered modern computational seismology which covers the entire range of seismology. He and his students combined the high-quality data coming from the Southern California Seismic Network and the sophisticated computational capability to determine a detailed crustal structure model for southern California. This model will be extremely useful for geological and engineering studies in the next generation.
Today, under the direction of Michael Gurnis (Director, 2009–Present), the Seismo Lab is a modern geophysical observatory that emphasizes the acquisition, analysis, and modeling of data pertaining to the structure and dynamics of the earth as well as other planetary bodies. This data originates from many sources including regional and global seismic networks, in-house analytic facilities (for example, high pressure mineral physics), oceanic research cruises, remote sensing (GPS, interferometric radar, Landsat, etc.), and geologic field mapping. Current Seismo Lab research incorporates all aspects of geophysics and earthquake geology including, but not limited to, regional crustal structure, the physics of earthquakes, the structure, chemistry, and convective flow of the earth's interior, oceanic and continental tectonics, and lithospheric deformation.