Every object has a fundamental period at which it vibrates. If an object is set in motion by an external force—such as earthquake ground shaking—at its fundamental period, the motion of the object will increase.
Damage to a building in an earthquake will be considerably more significant if the earthquake's vibrational characteristics match the fundamental period of the building, as the shaking is amplified. However, buildings can be damaged by shaking that is not the same as the building's fundamental period.
Spectral acceleration maps can be used to calculate the relative damage hazard of particular earthquake vibration periods.
Click on this link to go to Hazard Maps.
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