Spectral Acceleration (SA)

An Intensity Measure Type (IMT) defined by the maximum acceleration of a damped, single-degree-of-freedom harmonic oscillator.

The units are "g" (gravity) in OpenSHA.

This is further specified by:

• Spectral Period - the natural period (seconds) of the oscillator
• Spectral Damping - the degree of damping for the oscillator (usually 5%)

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