2001 - 2002 Public Lecture Series
at Caltech

Please join our second year of the Public Lecture Series!

November 13 - 8pm
SeismoSleuthing: What Scientists Can Learn from Historic and Prehistoric Earthquakes - Sue Hough, USGS Pasadena

January 22 - 8pm
What is Down There Causing the Earthquakes in the Los Angeles Region? - Gary Fuis, USGS Menlo Park

March 5 - 8pm
The Saga of Volcanic Unrest in Long Valley Caldera, Eastern California - David Hill, USGS Menlo Park

May 7 - 8pm
Using GPS to Study Faults and Earthquakes in Southern California - Nancy King, USGS Pasadena


November 13 - 8pm
SeismoSleuthing: What Scientists Can Learn from Historic and Prehistoric Earthquakes - Sue Hough, USGS Pasadena

Because seismology is a young science, we have few or no seismometer recordings of many of the most important earthquakes that have occurred in historic times. Such events include the great 1906 San Francisco earthquake, the 1811-1812 New Madrid (central U.S.) earthquakes, and a great earthquake now thought to have struck the Pacific Northwest in the year 1700. With perseverance and ingenuity scientists have managed to investigate these important earthquakes, in many cases piecing together remarkable results from the limited available evidence. This talk will discuss not only the methods that scientists use to "SeismoSleuth" but also recent results for a couple of notable historic earthquakes and their implication for the hazard posed by possible future occurrence of similar events.

January 22 - 8pm
What is Down There Causing the Earthquakes in the Los Angeles Region? - Gary Fuis, USGS Menlo Park

Most of us are aware that Los Angeles deserves its nickname "Shaky Town", but what is down there, below the earth's surface, that makes Los Angeles exceptionally prone to earthquakes? Since 1993, the Los Angeles Region Seismic Experiment (LARSE) has been trying to answer that question using techniques similar to ultrasound procedures in the medical industry. We have been obtaining seismic images of the "earthquake-producing machinery" beneath Los Angeles, just like those the ultrasound images of an unborn baby. One of our major discoveries is that the faults under the populated regions of Los Angeles, like the ones that produced the 1971 San Fernando and 1987 Whittier Narrows earthquakes, are connected northward to the San Andreas fault at great depth (~12 miles or more down). The rocks above these faults, including the rocks of the San Gabriel and Santa Susana Mountains, are moving upward and southward, slowly overriding Los Angeles, as the Earth's great plates in southern California are trying to move past each other around a bend in the San Andreas fault.

March 5 - 8pm
The Saga of Volcanic Unrest in Long Valley Caldera, Eastern California - David Hill, USGS Menlo Park

Long Valley Caldera and the Mono Craters - Inyo Craters form a large, geologically young volcanic field in east-central California near Mammoth Mountain. Recurring episodes of volcanic unrest in the Long Valley Caldera since 1980 have provided scientists a wealth of new insights on the inner workings of these voluminous, complex volcanic systems. This unrest has also underscored the importance of the interface between science and society as scientists, the public, and the media attempt to come to terms with the sometimes-unsettling behavior of the earth underfoot.

May 7-Tuesday
Using GPS to Study Faults and Earthquakes in Southern California - Nancy King, USGS Pasadena

Many people know that the Global Positioning System (GPS) can tell them where they are, to within a few yards, when they are hiking, driving, or sailing a boat. Earth scientists are now using especially precise methods, and a large new GPS network, to measure small movements of the earth's crust in southern California. In between earthquakes these movements are tiny, usually only a fraction of an inch each year, and are caused by slow, steady fault slip that does not cause shaking and cannot be felt. These small movements form patterns that scientists use to infer which faults are slipping, and how fast. This information is vital for estimating the earthquake hazard in southern California.