NR 2006-03
March 9, 2006

Contact: Ed Wilson
Mark Oldfield
Don Drysdale
(916) 323-1886

EDITORS: The 100th anniversary of the Great San Francisco Earthquake is April 18. The California Geological Survey (CGS) is regarded as the primary source of geological and seismological products and services for decision-making by California's government agencies, its businesses and the public. The following is a short feature about the state survey. It is the first of several releases related to California seismology and CGS’ work we will send in the weeks prior to the centennial anniversary.

Attached is a fact sheet with thumbnail descriptions of CGS’ earthquake-related programs. More information about those programs, as well as background that may be helpful in your coverage of the 1906 earthquake anniversary, is available on the CGS Web site at:

For more information, or to arrange interviews with CGS scientists about earthquake-related stories, please call (916) 323-1886.


SACRAMENTO -- Olaf Jenkins experienced the April 18, 1906 Great San Francisco Earthquake as a high school student in Palo Alto. Many years later, he recalled the events for California Geology magazine:

“Since my bed was walking all over my bedroom and I was sure that the house would land on its side, I just hung on. I had been sleeping soundly until just the very second the great temblor came. Although it seemed a long time shaking, it actually lasted only a fraction of a minute.

“I jumped up to look out my little window on the third floor of our home on the Stanford University campus. The view was of the beautiful sandstone buildings of Stanford University; but now there was a great cloud of dust rising. Only when the dust started to settle could I make out that not all was there.”

Jenkins, who already was leaning toward a career in geology at the time, would go on to become chief of the California Division of Mines from 1947 to 1958.

The California Division of Mines, which traces its history almost back to the Gold Rush, would evolve into the California Geological Survey (CGS), a branch of the Department of Conservation that works with other scientific and emergency response organizations throughout the state and around the world to protect public safety.

“Over the last 125 years or so, our focus has shifted,” said State Geologist Dr. John Parrish, one of Jenkins’ successors. “We still do geologic mapping and locate mineral resources, but studying and mapping seismic hazards to ensure that California is better prepared for the next large earthquake has become an important facet of our work.”

In 1851, one year after California was admitted to the Union, the Legislature named John B. Trask, a medical practitioner and member of the California Academy of Sciences, as Honorary State Geologist. In 1880, the California State Mining Bureau was established, but while the legislature recognized that geologists could provide valuable information, the study of seismic activity was an unknown subject. In fact, the Bureau’s annual report for 1906 made no mention of the earthquake. A later report explained:

“After the San Francisco disaster, what little funds the Bureau had and which would have been available for field work had to be used for the purpose of repairing damages sustained during the earthquake. The last legislature made no provision to rehabilitate the Bureau, although it sustained damage by breakage of cases and other losses to the extent of approximately $1,500.”

The Division of Mines (the State Mining Bureau was renamed several times over the years) created a geologic branch with a separate budget in 1929. However, it wasn’t until the magnitude 7.3 Arvin-Tehachapi earthquake of 1952 that it began to routinely map and study earthquakes.

From that humble beginning, a comprehensive seismic program has been developed that includes the mapping of surface fault traces, the development of landslide and liquefaction zones, the monitoring of how strong ground motion effects structures, and review of where schools and hospitals are located.

“Earthquakes were a fact of life in California in 1906, as they continue to be today,” Parrish said. “In terms of large earthquakes in densely populated areas, we’ve been fortunate. It has been relatively quiet since the Northridge earthquake of 1994. But the scientific community agrees that the probability of a damaging earthquake in a population center in the next 30 years is high.”

The anniversary of the 1906 earthquake, Parrish added, is an excellent opportunity to reflect on how far science has advanced in its understanding of earthquakes and how much more there is to learn.

“We cannot predict earthquakes and we certainly cannot prevent them,” Parrish said. “All we can do is try our best to understand them and learn to live with them by preparing as individuals, as members of a community, and as government leaders.”

That challenge was true in 1906, as well. In the 1980 California Geology article, Jenkins wrote of walking along the San Andreas fault after the great quake, seeing the heavily damaged water main leading from Crystal Springs Reservoir to San Francisco, and the need to prepare for future earthquakes:

“The force that it took to do that destruction simply amazed us. It was certain that anything in line of the moving fault had to give, and that feature many people found hard to believe. Very few people at that time had given a single thought to earthquakes, and even now it takes a lot of explaining to get the fact across.”