Observe the location of global earthquake activity from 1980–1995 in this NASA animation as well as the location of seafloor features, such as ridges and troughs, in this NASA world map. Comparing the locations of earthquakes and seafloor features reveals patterns that appear to coincide. These patterns provide information for further study in middle school on how the ridges and trenches formed and why earthquakes occur.

To view the Background Essay, Student Handouts, and Teaching Tips for this media gallery, go to Support Materials below. This resource was developed through WGBH’s Bringing the Universe to America’s Classrooms project, in collaboration with NASA. Click here for the full collection of resources.