Thomas Dibblee Jr., 93; Co-Wrote Key Study of Great Fault

Thomas Dibblee Jr., 93, prominent field geologist who mapped nearly a quarter of California, died Wednesday at his Santa Barbara home of unspecified causes.

Educated at Stanford University, Dibblee mapped areas for oil companies, the U.S. Geological Survey, UC Santa Barbara and himself. In 1953, he and a friend, Mason T. Hill, co-wrote a key study suggesting a more-than-350-mile displacement of land along the San Andreas fault over time. Their paper became a fundamental part of research on plate tectonics.

Mostly by hiking alone through California’s back country, Dibblee created about 500 maps charting nearly 40,000 square miles of the state.

He mapped large swaths of the Mojave Desert, the Coast Range and the Los Padres National Forest, earning a presidential volunteer action award in 1983 from President Reagan.

The Thomas Wilson Dibblee Jr. Geological Foundation was created to preserve and distribute his maps. Dibblee’s archives are housed at the Santa Barbara Museum of Natural History.