Ground Response Analysis is a method used in geotechnical engineering to evaluate how soil and rock respond to seismic activity, such as earthquakes. This analysis helps engineers understand how ground motion can affect structures built on or within the earth, ensuring safety and stability during seismic events. The process involves simulating the effects of seismic waves on different types of soil and rock layers. By using computer models, engineers can predict how these materials will behave under stress, which is crucial for designing buildings, bridges, and other infrastructure in areas prone to earthquakes, like California or Japan.