The main objectives of this study include: 1. To expand on a previous study and determine required unit energy levels imparted to a soil to induce liquefaction through laboratory testing of granular soils in the torsional shear device; 2. To determine the energy levels required for liquefaction under random loading, and compare them to the ones needed under sinusoidal loading; 3. To develop and validate a rational procedure to determine the liquefaction potential of soil deposits based on relationships between soil characteristics and energy levels, along with time series of design earthquakes. The validation procedure will include the analysis of time series and pore water pressure development records obtained during earthquakes.