2005 - 2006 Public Lecture Series
at Caltech

Please join our sixth year of the Public Lecture Series!

March 23 - 8pm - 2006
Parkfield 2004: Lessons from the Best-Recorded Earthquake in History
- Andy Michael, USGS Menlo Park

Obtaining high-quality measurements close to a large earthquake is not easy: one has to be in the right place at the right time with the right instruments. Such a convergence happened, for the first time, when the September 28, 2004, magnitude 6, Parkfield, California, earthquake occurred on the San Andreas fault in the middle of a dense and diverse network of instruments designed by the scientists of the Parkfield Earthquake Prediction Experiment to record what occurred before, during, and after this event. The resulting data reveal aspects of the earthquake process never before seen. These data, when combined with data from a sequence of at least 6 earlier Parkfield earthquakes dating back to 1857, provide important lessons about earthquake processes, prediction, and the hazards assessments that underlie important policies such as building codes.

January 19 - 8pm - 2006
The San Jacinto Fault: Little Brother of the San Andreas?
- Katherine Kendrick, USGS Pasadena

In southern California, the San Andreas fault splits into two different faults, the San Andreas and the San Jacinto faults. Both have produced large earthquakes in the past. The San Andreas is older, but just like a little brother, the San Jacinto is becoming more active and trying to outdo the San Andreas. In this presentation we will explore the risks associated with these two faults and examine the evidence for the relative activity of each fault. How do geologists study ancient earthquakes and find out how quickly faults moved in the past? We will look at the underground views of faults, and how we read the history that is preserved there.

Septmember 29 - 8pm - 2005
The 1906 Earthquake: Lessons Learned and Lessons Forgotten
- Mary Lou Zoback, USGS Menlo Park

The 1906 Mw7.8 earthquake on the northern San Andreas Fault marked the birth of modern earthquake science.  For the first time, the effects and impacts of a major seismic event were systematically investigated and documented in a detailed report. Scientists not only carefully mapped the entire 200-mile-long fault rupture, but they also mapped the fault south to the Mexican border, showing the San Andreas as a major geologic structure for the first time. They showed that the strongest shaking occurred in areas of “made land” (fill) and soft sediment including China Basin and the present day Marina district—two San Francisco neighborhoods heavily damaged again in 1989 during the Loma Prieta earthquake.  Their surveys of damage to structures concluded that destruction was closely related to building design and construction--a painful lesson oft repeated around the world.  Perhaps the most important scientific result to come out of the 1906 earthquake was the concept of an earthquake cycle. As earthquake science evolves, reanalysis of the 1906 earthquake data continues to yield new insights about that event and the behavior of large strike-slip faults in general. Looking to the future, a dense array of continuous GPS recorders in N. California, part of EarthScope’s Plate Boundary Observatory, can search for fault interactions and determine if an acceleration of strain rate precedes the next big earthquake as it may have prior to 1906.  Come and find out how we are still learning from “the big one” that happened 100 years ago!

Friday, November 3, 2006 7pm
The B4 Project: Scanning the San Andreas and San Jacinto Fau lt Zones
- Dr. Ken Hudnut, USGS Pasadena

Experience the visual wonder of a virtual tour along the San Andreas fault, as it has never been seen before.

In May 2005, the B4 Project team performed a high-resolut ion topographic survey of the San Andreas and San Jacinto fault zones in souther n California, in order to obtain pre-earthquake imagery necessary to determine n ear-field ground deformation after a future large earthquake (hence the name, 'B 4'), and to support tectonic and paleoseismic research. We imaged the faults in unprecedented detail using Airborne Laser Swath Mapping. The scientific purpose of such spatially detailed imaging is to establish actual fault slip heterogenei ty in (and after) a major earthquake, so as to help resolve classic 'great debat es' in earthquake source physics. We also succeeded in improving the methods use d for airborne imaging, such that very high quality imagery was obtained. All of the data collected are now openly available to the public over the internet.

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