On Thursday, February 6th at 8:00 PM the U.S. Geological Survey (USGS) Pasadena Office will continue their free Public Lectures with the second lecture of the 2002-2003 series. The presentation, entitled "Plumbing the Mysteries of the San Andreas Fault", will be given by Dr. Bill Ellsworth of the USGS Menlo Park Office.

Scientists are about to embark on a journey into the heart of the San Andreas Fault through the establishment of the San Andreas Fault Observatory at Depth (SAFOD). SAFOD will answer fundamental questions about how and why earthquakes occur through a comprehensive project to drill and instrument an inclined bore hole into the San Andreas Fault zone. The SAFOD is located on a segment of the San Andreas Fault mid-way between Los Angeles and San Francisco that moves through a combination of aseismic creep and repeating microearthquakes at the extreme northern end of the rupture zone of the 1966, Magnitude 6 Parkfield earthquake. Through material sampling, downhole measurements, and long-term monitoring directly within the San Andreas Fault Zone, SAFOD will provide direct information about the physical and chemical processes controlling faulting and earthquake generation within a major plate bounding fault.

Other lectures include:

"Are Foreshocks Mainshocks that Happened to Have Big Aftershocks ?" by Dr. Lucy Jones on March 18th

"Do Faults Talk?" by Dr. Greg Anderson on June 17th

All lectures are free and begin at 8 PM in Baxter Lecture Hall on the Caltech campus in Pasadena. There is plenty of free parking available.

For more information see http://pasadena.wr.usgs.gov/info/lectures/ or call 626-583-6801.

• USGS Public Lecture Series