Thomas McEvilly, 67; Seismologist Scrutinized Microquakes on Fault

Thomas V. McEvilly, a seismologist known for long-term monitoring of the San Andreas fault, died Feb. 22 of cancer in St. Louis. He was 67.

The UC Berkeley emeritus professor of earth and planetary science conducted a 15-year project with the U.S. Geological Survey to monitor the movement of the San Andreas fault at Parkfield, Calif.

As a principal investigator, McEvilly hoped to detect changes in the fault that could be used to predict large quakes. He helped install state-of-the-art borehole sensors and recording devices that allowed sensitive detection of microquakes, which seem to occur every one to two years at Parkfield. Along with a Berkeley colleague, he reported in 1999 that the pattern of microquakes could be used to predict the rate at which the fault is slipping deep underground and posing less risk of producing a major earthquake.