Station P224

Questions for Roland Bürgmann

How did you become a scientist/engineer?

As a kid, I always liked science, but didn't really think of it as a job possibility. It seemed like science was something you do for fun, not for work. Near the end of high school I was wondering if I should go on to study history or something related to the environment. So, I didn't really know exactly what was right for me, but decided to give geology a try.

When I started studying at the University of Tübingen in Germany, I was most interested in geochemistry, but through the influences of mentors and teachers, my interests focused in on structural geology and tectonics, and eventually on active tectonics and geodesy. It was most important to take opportunities to get involved in active research and get to work with scientists, early on. My research mentors freely shared their excitement and insights, and I learned that one doesn't have to be superhuman to do science or to have good ideas. As a professor, I now get to do science for fun and for work.

What is your job like?

As scientists, we never stop learning and studying. I get to spend substantial amounts of time reading and thinking about science others have done in research papers or learn about their work at scientific conferences. I also spend a lot of time talking about science. Part of my job is teaching courses at various levels. I also have a great time talking science with my students and postdocs, both in seminars and frequent one-on-one discussions of ongoing research projects.

What are you hoping to learn from your research?

Together with my students, postdocs and collaborators I study active fault systems, volcanoes and landslides. We use the Global Positioning System (GPS) and Synthetic Aperture Radar Interferometry (InSAR) to measure active surface deformation of these systems and complement these data with seismologic and geologic observations. This work relies on increasingly sophisticated models to better understand the mechanics of these dynamic systems. Recent research projects of the Active Tectonics group at University of California, Berkeley, focus on the active earthquake cycle and post-earthquake deformation in California, Tibet, Sumatra and Japan, volcanic activity on the Big Island of Hawaii and active landslides in the San Francisco Bay Area and in Colorado.

Hayward Fault

We may think of the San Andreas Fault as the contact between the Pacific plate and the North American plate, where the Pacific plate moves northwestward past the North American continent. But the San Andreas Fault isn't the only fault accommodating, or allowing, this motion between the plates.

P224 is located just east of the Hayward Fault, a fault running parallel to the San Andreas Fault in the San Francisco Bay area in California. GPS sites west of the both the San Andreas Fault and the Hayward Fault are moving northwest relative to stable North America (Figure 2). P224, on the North American side of the Hayward Fault, also moves to the northwest. Even relative to the Sierra Nevada, there is still some motion, showing that the Bay Area faults to the east of the Hayward Fault are also active. Plate motion doesn't happen all along one single fault. It affects a plate boundary zone, which can extend deep into a continent.

If we compare the motion of P224 with station P181 located across the Hayward Fault (Figure 1), we can see that the relative velocity between the stations is about 9 mm per year. Given the location of the stations, this suggests that the slip rate on the fault must be close to this number.

The Hayward Fault is one of our most important research targets in the San Francisco Bay Area. The fault had a large (magnitude ~7) earthquake in 1868, but also creeps, or slips steadily by a few mm each year, on substantial portions of the fault surface. We use GPS data from P224 and other stations to estimate the slip rate on the Hayward Fault, and to determine where the fault is creeping and where it is locked.

To explore the Hayward Fault in Google Earth, check out the USGS Active Traces of the Hayward Fault virtual tour.

Spotlight Questions