Abstract
The variance of peak horizontal accelerations and velocities of the Japanese strong-motion data set is examined. The standard errors of the data from the empirical attenuation relationships are calculated. The standard error decreases with increasing magnitude, with decreasing the distance, and with increasing the amplitude. The amplitude dependence of the error seems much stronger than the magnitude and distance dependences. The distance dependence can be caused by the effects of scattering and absorption of seismic waves in the path. The strong amplitude dependence can be interpreted by multiplying of the effects of the maginitude and distance dependences.
