Before revision: 350px|Ground motion hazard map for Hawaii, based on a 2% probability of exceeding 0.2 second spectral acceleration at 5 Hz in 50 years Spectral Acceleration (SA) is the approximate equivalent acceleration of a structure due to an excitation acceleration.
After revision: 350px|Ground motion hazard map for Hawaii, based on a 2% probability of exceeding 0.2 second spectral acceleration at 5 Hz in 50 years Spectral Acceleration (SA) is the resulting acceleration of a structure due to an exciting acceleration.