Optimal digitization of earthquake records

The optimal time interval for sampling an earthquake timehistory in order to recover the original record in a unique manner is derived. If the sampling time interval is too large, the high frequency components of the timehistory can ‘impersonate’ low frequencies. This results in ‘aliasing’, in which is a major source of distortion in the reconstruction of the original timehistory from its discretized values. In the present study, the optimal sampling time interval known as the Nyquist interval in signal processing is derived. The results indicate that if the optimal time interval is exceeded, loss of information occurs. The use of a smaller time interval results in additional computer cost without any increase in the information necessary to reconstruct the original time history.