April lecture series marks centennial of 1906 San Francisco earthquake

With 1,100 miles of geologically active coastline and most of its 36 million people living near the coast, California is at risk from both earthquakes and tsunamis. In a series of lectures in Santa Cruz on April 19 and 20, titled "Quaking 'n' Breaking: Earthquakes to Tsunamis: Then and There, Here and Now," experts will examine these risks in the context of local disaster history and recent global calamities.

The talks mark the centennial of the April 18, 1906, San Francisco earthquake. On Wednesday, April 19, local historian Sandy Lydon and UC Santa Cruz geologist Gary Griggs will discuss the earthquake history and present-day geological realities of central California. On Thursday, April 20, oceanographer Bruce Jaffe and geologist Harvey Kelsey will examine the threat of tsunamis.

Sponsored by the Seymour Center at UCSC's Long Marine Laboratory, the lectures will take place at 7 p.m. at the UCSC Inn and Conference Center, 611 Ocean Street, in Santa Cruz. Tickets cost $6 per evening or $10 for the series for the general public ($5 per evening or $8 for the series for Friends of Long Marine Lab members). For tickets and information about the lectures, call (831) 459-3800.

Griggs, a professor of Earth sciences and director of the Institute of Marine Sciences at UCSC, and Lydon, who teaches history at Cabrillo College, are coauthoring a book on the history of natural disasters in the Monterey Bay Area. In their talks, Griggs and Lydon will discuss the major seismic events that have struck the area during the past several hundred years, including the 1906 San Francisco earthquake and the 1989 Loma Prieta earthquake. Griggs will provide insights into the geological mechanisms underlying the quakes, and Lydon will describe how human populations responded to the calamities.

Jaffe and Kelsey are former students of Griggs who earned their Ph.D.s in Earth sciences at UCSC. Jaffe is now an oceanographer at the U.S. Geological Survey Pacific Science Center in Santa Cruz. He will present highlights from his trip to Sri Lanka and Indonesia to study the effects of the devastating tsunami that struck southern Asia in 2004. Triggered by an undersea earthquake, the tsunami rose 100 feet above the coast and traveled 3 miles inland. Jaffe found vast and widespread devastation, especially in northwest Sumatra. In some areas, however, the inhabitants had escaped destruction by wisely fleeing inland after sensing the quake.

Kelsey, an adjunct professor and research associate in geology at Humboldt State University in Arcata, specializes in the study of earthquake history. He will present findings on the Cascadia subduction zone, a major offshore fault that extends from southwestern Canada to northern California. The Cascadia fault has been the main source of earthquake-generated tsunamis that have struck the West Coast in the past. Layers of sand deposited in an Oregon coastal lake during the past 4,600 years bear testimony to past earthquakes and tsunamis along this zone, Kelsey said.