After Hyogoken-Nambu earthquake, it is aware that the earthquake motion in the fields near inland faults has to be considered in aseismic design of structures, although this type of motion is rare during the life of structure. For such a strong seismic motion, elasto-plastic analysis must be adopted in aseismic design to trace the process of damages in structure during the earthquake. In consequence, the reliability of assessment of seismic input motion plays a very important role in aseismic design. Unlike that in old standard, where the seismic effects on structures were determined associated with the aseismic potential of structures based on experienced earthquake disaster, the seismic motion should be defined as a natural phenomenon, unique to but unrelated to structure itself. It is well known that the local geological conditions and surface soil affect seismic motion considerably. Therefore, seismic input motion is to be given on opening engineering bedrock (shear wave speed above 400m/s) and local effects are to be evaluated by analyses together with the analysis of structures.