Earthquake loading comprises the forces from inertia of mass of structure. These forces are generated due to shaking of foundation of a building by seismic disturbance. The effect of translational forces from inertia of a structure is more significant than rotational or vertical component of shaking and seismic resistant design pay concentration to this force.
Dynamic response of a structure against shaking of ground produces the magnitude of loading due to earthquake. On the basis of structural properties and past seismic record of a region, seismic loading are determined.
Now we will know other form of earthquake forces like forces due to–
c. Active faulting beneath foundation
d. Vibration generated liquefaction
These sources of forces are local. But they sometimes become too massive to challenge any economic seismic resistant design. During site selection for a structure a earthquake engineer must consider these geological and geotechnical considerations and alternate location should be chosen to avoid earthquake forces of these form.