2002 - 2003 Public Lecture Series
at Caltech

Please join our third year of the Public Lecture Series!

November 14 - 8pm
The Pulse of the Earth: How and Why We Monitor Earthquakes -Doug Given, USGS Pasadena

February 6 - 8pm
Plumbing the Mysteries of the San Andreas Fault - Bill Ellsworth, USGS Menlo Park

March 18- 8pm
Are Foreshocks Mainshocks that Happened to Have Big Aftershocks? - Lucy Jones, USGS Pasadena

June 17 - 8pm
Do Faults Talk to Each Other? - Greg Anderson, USGS Pasadena


November 14 - 8pm
The Pulse of the Earth: How and Why We Monitor Earthquakes -Doug Given, USGS Pasadena

When the ground shakes, millions of southern Californians tune in to find out about the earthquake. Where was it? How big was it? How do seismologists find out?

February 6 - 8pm
Plumbing the Mysteries of the San Andreas Fault - Bill Ellsworth, USGS Menlo Park

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 earthquake occur through a comprehensive project to drill and instrument an inclined borehole into the San Andreas Fault zone. The SAFOD is located on a segment of the San Andreas Fault midway 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 at seismogenic depths, SAFOD will provide direct information about the physical and chemical processes controlling faulting and earthquake generation within a major plate-bounding fault.

March 18 - 8pm
Are Foreshocks Mainshocks that Happened to Have Big Aftershocks? - Lucy Jones, USGS Pasadena

Every earthquake makes another earthquake more likely. Although the prediction of a particular earthquake remains impossible (it really is!), seismologists do have information about the probability of future earthquakes. Most of these triggered earthquakes are smaller than the first event and we call them aftershocks. A few percent of the time the triggered earthquake is larger than the first one and we change the names and call the first one a foreshock. The probability of triggering another earthquake has been quantified, so that seismologists can make relatively accurate predictions of the likely future earthquakes once the first one has occurred. This talk will describe the how we determine the probabilities, what makes a larger earthquake more likely, and how the USGS calculates and distributes this information.

June 17-Tuesday
Do Faults Talk to Each Other? - Greg Anderson, USGS Pasadena

In the past decade, seismologists have discovered that faults may “talk” to each other, and large earthquakes may be related to one another, in ways which were previously unknown. By studying earthquakes in California and elsewhere, scientists have discovered that earthquakes can sometimes “jump” from one fault to another, growing larger and more dangerous in the process. The recent Denali Fault earthquake in Alaska grew in this way to become one of the largest earthquakes in the United States since 1857. We are also learning how large earthquakes can sometimes have an impact on the behavior of other earthquakes in the region, including those which happen far away from or long after the first large event; in just one example, the 1992 Landers earthquake in the Mojave desert triggered swarms of earthquakes as far away as Yellowstone National Park. Come and learn about some current research on the “conversations” faults have with each other, and find out how improving our understanding of these conversations may help earth scientists to better quantify the threat earthquakes pose to urban areas throughout the United States and the world.