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Harry O. Wood Papers

Identifier: WoodHO

Scope of the Collection

The papers of Harry O. Wood were transferred to the Caltech Archives from the Seismology Laboratory. The initial donation, now occupying twenty-two document boxes, was made in 1976; it was supplemented with two more boxes about ten years later. The supplemental material has been processed separately from the original portion.

The collection consists mainly of correspondence (over 19 boxes) of a personal and general nature. The personal correspondence covers mainly the years from 1912 to 1954. It contains numbers of letters to and from prominent geologists, seismologists and private citizens of the day. Also included are letters with various manufacturers, which were furnishing, or attempting to furnish, equipment and material for the instruments used in the seismological laboratories, which needed special clocks, motors, paper, etc. There are also letters from observatories throughout the world, individuals inquiring about the earthquake situation in Southern California, which Wood always cordially answered, and reports of earthquakes from volunteers living in California. General correspondence is organized by topic. Three boxes of Carnegie Institution of Washington correspondence features especially the letters between Wood and Arthur L. Day and John C. Merriam. This correspondence is mainly concerned with the establishment of the central station for seismological investigation in Pasadena. Two boxes of Seismological Society of America correspondence contain letters to and from Ralph Arnold, Perry Byerly, George D. Louderback and S. D. Townley. Material on the 1857 California earthquake can be found in the Louderback file. There are three boxes of U.S. Coast and Geodetic Survey correspondence plus, in the supplement, correspondence files on specific earthquakes. Also in the supplement are correspondence files from Wood's period at the Hawaiian Volcano Observatory from 1912 to 1918.

In addition to the correspondence, the papers contain manuscripts and printed materials in the form of miscellaneous manuscripts, memoranda, notes, records, reports, reprints, and copies of the publication Volcano Letter.


  • 1905-1954



Collection is open for research.

Publication Rights

Copyright has not been assigned to the California Institute of Technology Archives. All requests for permission to publish or quote from manuscripts must be submitted in writing to the Head of the Archives. Permission for publication is given on behalf of the California Institute of Technology Archives as the owner of the physical items and is not intended to include or imply permission of the copyright holder, which must also be obtained by the reader.

Biographical / Historical

Harry Oscar Wood (1879-1958) was a Research Associate in Seismology at Caltech from 1925 to 1955. Born in Gardiner, Maine, he received bachelor's and master's degrees from Harvard. In 1904 he became an instructor in mineralogy and geology in the geology department at Berkeley, which was led at that time by Andrew C. Lawson. After the 1906 San Francisco earthquake, Wood's interests shifted to seismology. Under Lawson's direction, he wrote a detailed report on the 1906 quake for the State of California's Earthquake Investigation Commission. Wood resigned his position at Berkeley in 1912 to work for T. A. Jagger at the newly founded volcano observatory at the Kilauea Volcano on the island of Hawaii. Wood left Hawaii late in 1917 to join the Army Engineer Reserve Corps for the duration of World War I. Working in Washington, DC, he came into contact with both George E. Hale and John C. Merriam, two to the most influential scientists of their day. Merriam was an eminent paleontologist who had been a professor at Berkeley during Wood's time there. Hale, a solar astronomer, was the director of the Mount Wilson Observatory in Pasadena. During the war Hale had established the National Research Council (NRC) to coordinate scientific efforts nationally. After the war, Merriam became director of the NRC and then, in 1921, president of the Carnegie Institution of Washington. Both men would play a role in Harry Wood's future.

Although Wood remained in Washington for several years after the war as an NRC staff member, his dream was to study local earthquakes in California, an activity he called "provincial investigation." This was to be distinguished from the European-style study of earthquakes at long distance known as teleseismic study. Wood finally convinced Merriam that the Carnegie Institution should fund a seismological research program in California. Headquartered in Pasadena, the program at first operated out of the offices of the Mount Wilson Observatory. Wood envisioned a network of five seismic recording stations. Eventually, in 1924, Hale came to the rescue. As a trustee of the California Institute of Technology, he persuaded that institution to fund the construction of a new seismological laboratory. This building was located west of the Caltech campus in the San Rafael hills and was ready for use in December, 1926. Meanwhile, Wood, with the help of Mount Wilson astronomer John Anderson and others, was developing seismographic instruments designed to record local shocks.

The Seismology Laboratory was operated jointly by Caltech and the Carnegie Institution until 1937, when the Carnegie withdrew from the partnership. With the title of Research Associate in Seismology, Wood remained in charge of the operation of the lab and the network. In 1930 Caltech hired its first professor of geophysics, Beno Gutenberg. Charles Richter, at first Wood's graduate student assistant, was subsequently appointed Professor of Seismology. The scientific work of Gutenberg and Richter, including the invention of the earthquake magnitude scale in 1935, made the Seismology Laboratory world famous.

In 1935 Wood contracted a severe infection which affected his nervous system. Although he recovered sufficiently to continue his scientific work, he never fully regained his health. He died in Pasadena on February 4, 1958.


12 linear feet (24 boxes)

Language of Materials


Guide to the Harry O. Wood Papers
In Progress
Processed by Charlotte E. Erwin, Associate Archivist; machine-readable finding aid created by Xiuzhi Zhou
Language of description
Script of description

Repository Details

Part of the California Institute of Technology Archives and Special Collections Repository

1200 East California Blvd.
MC B215-74
Pasadena California 91125 United States of America
(626) 395-2704