What can GPS tell us about future earthquakes?
This animation by UNAVCO shows that GPS stations along the coast of Japan had been moving to the west before the March 11, 2011 earthquake, and rebounded back to the east following the earthquake. This animation compares that subduction zone with a mirror-image subduction zone in the Pacific northwest by illustrating how the shallow portion of the Cascadia plate boundary is locked by friction thus compressing the overlying North American Plate in a NE direction during subduction of the Juan de Fuca Plate. Using a spring to emphasize the strain within the overlying plate, we will see the displacements of GPS receivers along the entire leading edge of the North America continental margin. Ultimately, the continental margin will rebound suddenly to the southwest as the stored elastic energy is released for the first time since the last great Cascadia earthquake on January 26, 1700.
This animation was made by UNAVCO in collaboration with the Cascadia EarthScope Earthquake & Tsunami Education Program CEETEP and IRIS. The animation with related resources can be found on the UNAVCO site.