A series of centrifuge tests were conducted on the 150 g-ton RPI centrifuge to investigate the effect of soil permeability on the response of single piles and pile groups to liquefaction and lateral spreading. More specifically, two models, simulating a gentle infinite slope of a liquefiable layer on top of a layer that would not liquefy were tested in a large laminar box. The models were instrumented with pore pressure transducers and accelerometers, as well as with lateral LVDTs mounted on the flexible wall, and the piles were instrumented with strain gauges along their lengths. The results were used to generate visual animations of the dynamic response of the soil-pile systems. Visualization techniques proved to be very important in understanding complex phenomena like excess pore pressure buildup and dissipation, and dilation patterns near piles. This article presents experimental results and analysis of these centrifuge tests.