Bruce A. Bolt, 75; Studied Earthquakes to Improve Building Safety

Bruce A. Bolt, the UC Berkeley seismologist who used strong-motion sensors along fault lines and records from historic earthquakes to improve seismic safety of modern structures, has died. He was 75.

Bolt died Thursday of pancreatic cancer at Kaiser Permanente Medical Center in Oakland.

With an eye toward drafting safer building codes, Bolt worked to predict what the ground would do, and the resulting damage, if an earthquake occurred on a certain fault.

He used synchronized seismographs to measure ground movement along faults and studied similar research projects in Japan and Taiwan to determine why quakes jolt some areas harder than others in active seismic zones.

Looking at earthquake records, he also studied seismic wave activity, rock formations and soil composition at various distances from epicenters, their interaction and the resulting damage.

In studying the 1989 Loma Prieta earthquake, for example, he determined that San Francisco’s Marina district, the Nimitz Freeway and certain areas of Oakland suffered heavy damage while areas near the Santa Cruz County epicenter fared better because of the areas’ varying underground rock formations.

“Los Angeles has considerable variation in crustal formation that will swing waves in certain ways, depending on where the earthquakes occur,” he told The Times in 1992. “That can be calculated. It hasn’t been done yet, but it can be.”

Such calculations, he said, could influence building codes in areas where heavy shaking would be expected.

Bolt was a longtime member and former chairman of the California Seismic Safety Commission, which praised him in a statement as “one of California’s most influential policymakers in earthquake safety,” adept at increasing public awareness and motivating legislators.

A native of Largs, Australia, Bolt moved to Berkeley in 1963 to head what is now the Berkeley Seismological Laboratory. He stepped down as director in 1989 but continued to teach and conduct research until 1993, and was still consulting and giving speeches until his death.

Bolt was adept at working with engineers, which enabled him to use his research to influence the retrofitting of old structures and the design of new ones to improve their seismic safety.

“The goal is to have a situation where we can boast, ‘Let the earthquake come,’ ” he said in a 1996 lecture at the University of Washington.

Bolt helped develop legislation establishing the Southern California and Bay Area Earthquake Preparedness Projects, the California Earthquake Education Project and seismic hazard mapping. He also worked for legislation providing earthquake safety requirements for private schools, hospitals, unreinforced masonry buildings and mobile homes as well as disclosure of earthquake weaknesses to potential home buyers.

He lectured widely on earthquake preparedness and pushed for and helped design a long-term exhibit on the subject at the Academy of Sciences in San Francisco’s Golden Gate Park, where he was a trustee and board president.

In his research, Bolt spent little time on the popular pursuit of scientific prediction of date, place and size of earthquakes, a research area he felt held little promise.

“We have to be prepared to accept the fact,” he told The Times in 1985, “that earthquakes may occur with no warning.”

Bolt served as a consultant for the construction of Egypt’s Aswan High Dam, the Trans-Alaska Pipeline and myriad projects in California, including Pacific Gas & Electric’s Diablo Canyon nuclear power plant.

He wrote or contributed to several books, including “Earthquakes: A Primer” in 1978, now in its fifth edition, and “Inside the Earth: Evidence From Earthquakes” in 1982.

The seismologist earned bachelor’s, master’s and doctoral degrees in science and a doctorate in applied mathematics from the University of Sydney, where he taught math from 1954 to 1962. He moved into seismology after developing an interest in the mathematical modeling of Earth’s interior.

Bolt, who became a U.S. citizen in 1972, is survived by his wife, Beverley; daughters Gillian Bolt Kohli of Wellesley, Mass., Helen Bolt Juarez of Fremont, Calif. and Margaret Barber of Rumson, N.J.; a son, Robert, of Hillsborough, Calif.; a sister, Fay Bolt, of Sydney, Australia; and 14 grandchildren.

A memorial service is scheduled at 3 p.m. Friday in the UC Berkeley Faculty Club. Memorial donations may be sent to the California Academy of Sciences, 875 Howard St., San Francisco, CA 94103; or to the Bear Valley Tennis Club, c/o Treasurer Ann Wolff, 151 Pepper Court, Los Altos, CA 94022.