Earthquakes are among the most destructive natural disasters on our planet. Over history, enormous engineering and research efforts have been devoted to the study of causes and consequences of earthquakes, the prediction and forecasting of future earthquakes, the determination of ground motion intensities in a particular site, and the seismic response assessment and the mitigation measures for various types of structures and foundations. All these efforts have been intended simply to keep structures and their contents from falling down and causing damage and to keep people safe during earthquakes.