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Slips in the earth cause stress to fault lines, ultimately resulting in an earthquake. Scientists at the U.S. Geological Survey use globes such as the one shown here to study the inner surfaces of the earth and how slips and stresses may occur.
The Visitor Center at the U.S. Geological Survey in Menlo Park, Calif., catalogs earthquake surveys from past decades.
This poster is just one of the many that blanket the walls of the U.S. Geological Survey in Menlo Park, Calif., commemorating the San Francisco earthquake of 1906.