On web page: a map that gives us an overview of the SF area.

I. San Andreas Fault

We start on a field trip put together by Joe Dellinger of Stanford University. His first photo was taken at the red cross on Map 2 on the Web page. The San Andreas fault trace is along the linear lakes (actually reservoirs) to the west.
Map 2:

Start on the field trip. (http://sepwww.stanford.edu/oldsep/joe/fault_images/BayAreaSanAndreasFault.html) Answer the following questions as you go.

1. Why is the valley containing the lakes so very straight?

2. Why is the San Francisco Bay even here?

3. Why are strike-slip faults good places for lakes?

The epicenter of the 1906 earthquake was north of the areas described here. Look HERE at some photos of the damage and offset recorded.

The other major fault in the Bay area, the Hayward fault, seems to experience fault creep most of the time, a motion of only a few millimeters at a time, which does not allow strain energy to accumulate for a major earthquake.

The tour of the Hayward fault has been organized by Dr. Sue Ellen Hirschfeld at Cal State-Hayward. The tour starts in Fremont (see map 1 above) and continues north to Hayward and Berkeley.

Many of the photographs were taken while looking across the fault. That is, the photographer stood on one side of the fault looking at things on the other side of the fault. The right-lateral motion of the fault then becomes clear.

4. Describe right- and left-lateral fault motion in your own words. (might want to look at the book).

Start the tour (http://www.mcs.csuhayward.edu/~shirschf/tour-1.html ) and follow their instructions. That is, click on the Fremont to South Hayward link, then the Downtown Hayward link, etc.

5. Draw a little sketch here of the offset of
the stream valley in South Hayward.

6. Fence at the Holy Sepulchre Cemetery: Imagine walking past the break in the fence and looking back to where this photo was taken. Will you still see right-lateral movement?

In downtown Hayward notice the movement around C and B street and in the alley. Subtle, but geologists notice these things!

Residential area north of Hayward, Rose and Prospect Streets: there appears to me to be about 20 cm of offset if this curb from the first photo to the last. What do you think?

7. Calculate the creep in the Hayward fault in this area in cm/year.

8. What kind of damage has been caused by the Hayward Fault in this area in the past 50 or so years?

9. As we virtually travel north along the Warren freeway, answer for yourself, what is a rift valley?

Orient yourself in the Oakland-Berkeley area and follow the trace of the fault in the aerial photos. Let's visit Berkeley stadium. The fault trace runs right through the stadium, from goalpost to goalpost.

10. Look at the offset here. There has been about 33 cm of offset from 1923 to 1993. So the creep in the Hayward fault in this area is ______________ cm/year. Is this the same amount of creep as we measured in Hayward? Speculate on why.

What is the history of earthquakes on this fault?

Visit the recent earthquakes page (http://quake.usgs.gov/recenteqs/Maps/San_Francisco.htm). The most recent earthquake on the Hayward fault was when, where, and how big? (http://quake.usgs.gov/recenteqs/FaultMaps/San_Francisco.htmThis USGS map will give you the name of the fault as you move the mouse over a given fault.)

Last updated: Feb. 5, 2004.

You are visitor number since Feb. 5, 2004.

SCI 210 section 3 syllabus SCI 210 section 7 syllabus List of Explorations/Virtual fieldtrips andrea.koziol@notes.udayton.edu Dr. Koziol's homepage UD Dept. of Geology Home

The graphics on this page are courtesy of Jelane's free web graphics