Tide Response (IMAGE) California Institute of Technology Caption The outline of each ellipse represents the motion the ground makes as the earth flexes in response to the time and space dependent tides. There is an ellipse for each of the GPS sites used in the study, and the color indicates the amplitude of the tidal response movement. Credit California Institute of Technology Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.