Urban Sprawl


To evaluate urban development in an earthquake-prone region.


  • 1973 and 1999 satellite images of the San Francisco Bay area


As a geologist who is also an expert in using satellite data, you are working on a special assignment.You have been hired by officials from the city of San Francisco to study the city’s growth over that past 25 years or so. Officials are especially interested in finding out whether or not development–houses, roads, shops, and schools– is getting too close to active faults.


Urban SprawlFor this important work you have selected 1973 images from Landsat 1 and 1999 Images from Landsat 7. You may also want to refer to a map of the region at TopoZone.com.

On the “false-color” image above, color has been added to enhance the features you want to study. Red represents open land; light blue represents buildings, roads, parking lots, and other development; and yellow represents seismic events that have occurred during the past 100 years.

You have already studied the entire area and have chosen three smaller regions for more careful examination. If you click on the link to the satellite data below, you will have access to 1973 and 1999 images for your analysis. (More Information)

San Francisco Satellite Data

Examine each pair of small images. Use them to find out whether houses, roads, shops, and schools are getting too close to active faults. Good Luck!


You have been asked to appear before the San Francisco Bay-Area Council. They want a report of your results. Has growth over the past 25 years come too close to active faults? The Council requires a carefully typed “Executive Summary” of your findings with separate diagrams or images that illustrate the points you are making. (You may print out images from this Web site.)