Lasting Memories

Manuel G. Bonilla
1920-Feb. 18, 2006
Palo Alto, California

Manuel G. "Doc" Bonilla, an engineering geologist who mapped earthquake faults on the Peninsula and around the world, died February 18 at his Palo Alto home after a long struggle with stomach cancer. He was 85.

During 47 years at the U.S. Geological Survey, and another dozen after he retired in 1994, Mr. Bonilla studied earthquakes, the faults that generate them, and ways of reducing their risks.

He worked in the Bay Area, and in Taiwan, mainland China, Guatemala and Guinea. He tracked 19 earthquakes, the Alaska Good Friday earthquake of 1964 -- the largest ever recorded -- and the Loma Prieta earthquake of 1989.

Most famous, perhaps, was 1964 when Mr. Bonilla and longtime colleague Julius Schlocker were scouting the geology inside the big hole that PG&E was building for a nuclear reactor at Bodega Head in Marin County near the San Andreas Fault. They found an active fault passing through the hole; the reactor was canceled. They got an award. Mr. Bonilla received many awards. The most impressive was the Interior Department's highest award, the Distinguished Service Award, which credited Mr. Bonilla with "evaluating and reducing earthquake and other geologic hazards for the U.S. Geological Survey." The 1995 award also praised Mr. Bonilla's detailed report on the geology, history and earthquake effects of the Loma Prieta Earthquake on the Marina District in San Francisco.

Fellow geologist Carl Wentworth of Ladera remembers working with "Doc" just two weeks before his death. They were preparing a contour map of the bedrock underlying younger deposits in the quadrangle surrounding San Bruno Mountain. Dr. Wentworth is preparing the map for publication. "We joked and kidded and gave each other a hard time," said Dr. Wentworth. "Doc was a very quiet gentle man, very capable, very meticulous."

Manuel Bonilla was born in 1920 on a small farm near Sacramento, the youngest child of Spanish immigrant parents. He earned a bachelor's degree in geology from U.C. Berkeley in 1943, and a master's from Stanford in 1960.

During World War II, Mr. Bonilla used his geologic knowledge for Army intelligence to evaluate cross-country routes for use by tanks and military vehicles, according to Menlo Park geologist and colleague Porter Irwin.

After joining the geological survey in 1947 when it was located in the Old Mint in San Francisco, Mr. Bonilla was part of the first team to come to the new campus in Menlo Park in 1953.

Mr. Bonilla is survived by his wife, Ruth; son Roger of Sunnyvale; daughters Janice of San Jose and Laurie of Mountain View; and two grandchildren.