CAESAR II uses linear-elastic 3D beam elements. The loads are user defined, applied to the node points, and remain constant.

Deformation of the Floor: You would have to specify this as displacements of the (support) nodes.

Buoyancy due to Liquefaction: I suppose you could simulate this by altering the densities, but this would be a manual adjustment.

Abrupt Deformation of the floor: If you were running dynamics this could be done with a psuedo-static displacement. In statics you would have to displace a portion of the model to approximate this.

Seismic Wave Propagation: CAESAR II can perform a (dynamic) response spectrum analysis, but I don't think this will be sufficient. CAESAR II can also perform a time history analysis, which may do what you want, but the load definition will be tedious at best.