A curve showing the mathematically computed maximum response of a set of simple damped harmonic oscillators of different natural frequency(ies) to a particular record of earthquake ground acceleration. Response spectra, commonly plotted on tripartite logarithmic graph paper, show the oscillator's maximum acceleration, velocity, and displacement as a function of oscillator frequency for various levels of oscillator damping. A computational approximation to the response spectrum is referred to as the pseudorelative velocity response spectrum (PSRV). These curves are used by engineers to estimate the maximum response of simple structures to complex ground motions. For example, the 5-percent spectral acceleration at 1 second is the maximum acceleration of the top of a structure with 5 percent damping whose natural period of vibration is 1 second when subjected to a given input ground-acceleration record.