Interview with Clarence R. Allen

An interview in two sessions in April 1994 with Clarence R. Allen, emeritus professor of geology and geophysics in the Division of Geological and Planetary Sciences. Dr. Allen matriculated at Reed College in 1942, then spent three years (1943 to 1946) in the Army Air Corps before returning to graduate with a major in physics. He entered Caltech as a graduate student in geophysics in 1949 (MS, 1951; PhD in structural geology and geophysics, 1954). After a year as assistant professor at the University of Minnesota, he came to Caltech as an assistant professor in 1955, becoming a full professor in 1964. In this interview, he discusses growing up in Southern California; his early interest in science and the outdoors; and his wartime career as a navigator in the Army Air Corps. He recalls his years as a Caltech graduate student and his thesis work on the San Andreas fault; his work on glaciology with Robert P. Sharp; his growing interest in seismology; and his work with Charles Richter, Hugo Benioff, and Beno Gutenberg in Caltech’s Seismological Laboratory. He discusses the interplay at the Seismo Lab in the 1950s between Richter and Gutenberg; the changes wrought by the advent of Frank Press as director in 1957; and the work of Kerry Sieh in paleoseismology. Praise for the division chairmanship (1952-1968) of Robert Sharp. Comments on the “science” of earthquake prediction and failed prediction efforts by the Russians and the Chinese. The rise of Caltech to public prominence in the area of seismology. He discusses his own work on earthquake faults as they bear on the assessment of seismic hazards and notes the usefulness of probabilistic analysis in long-term planning to avoid earthquake damage