A plot of the maximum response of a series of single-degree-of-freedom damped oscillators (elastic systems) as a function of their natural periods, or frequencies, when the oscillators are subjected to a vibratory ground motion. The maximum values of acceleration, velocity, and/or displacement of an infinite series of single-degree-of-freedom system subjected to an earthquake. The maximum response values are expressed as a function of natural period for a given damping. The response spectrum acceleration, velocity, and displacement values may be calculated from each other assuming a sinusoidal relationship between them.