Book ChapterDigital resources are stored online in your NSTA Library.
One person described how the bedroom wall moved across the room. Another watched as a huge wave of concrete traveled along the highway. We all saw the massive destruction
when one bridge roadway collapsed on top of another. The earthquake in the San Francisco area that coincided with the 1989 World Series
gave us a glimpse of the power and energy in our planet. The Earth is not of uniform
density. Longitudinal and transverse waves, called P and S waves, travel through the Earth as a result of the quake. This chapter highlights how the differences in P and S wave behaviors can give clues about the structure of the Earth, while also helping to locate the epicenter of the quake.