Talk Wednesday on 1906 quake

A U.S. Geological Survey scientist will lecture Wednesday about the great San Francisco earthquake of 1906. The 100th anniversary of the event is next month.

Mary Lou Zoback, senior research scientist for the USGS in Menlo Park, Calif., is scheduled to speak about "lessons learned, lessons forgotten and future directions."

The free public lecture begins at 7 p.m. in the auditorium of the Salt Lake City Main Library, 210 E. 400 South.

Zoback earned her doctorate from Stanford University in 1978; today she is a senior research scientist with the Geological Survey and regional coordinator for its Northern California Earthquake Hazard Program.

Early in her career with the agency, she worked in Utah, near Nephi, studying the Wasatch Fault, which runs through Salt Lake City.

"We were trying to understand what might control what we call the segmentation of the Wasatch Fault," she said in a telephone interview. "It's a very long fault."

In past earthquakes, the fault would break in one or another of its separate segments, but not along its full extent. That is different from the San Francisco 'quake, in which 300 miles of the San Andreas Fault broke on one terrible day.

Lessons were learned a century ago, some of which were forgotten, she said. The biggest of these was "the vulnerability of what they called 'made ground,' " Zoback said. Today that material would be called fill.

"We still have continued to build" on fill material, she said. The 1989 Loma Prieta quake damaged many buildings built on fill. Besides buildings, pipelines are built through areas of artificial fill.

"Unlike hurricanes or tornadoes, earthquakes are going to strike without any warning at all," Zoback said. In seconds, strong shaking travels through whole regions and towns.

People "really need to be prepared ahead of time."

If they live in structures built before modern earthquake codes of the 1970s, they should ask if the buildings have been strengthened. Families should plan how to get out and where to meet in case of devastation.

They also should stock emergency supplies. But, she added, many Utahns already know that.

The University of Utah Seismograph Stations and the Utah Seismic Safety Commission are sponsoring the lecture.

April 11 is the 40th anniversary of the seismograph stations. A week later, April 18, is the 100th anniversary of the earthquake that, according to the U., killed 3,000 and left 250,000 homeless in San Francisco.