A Random Model for Half-Amplitude Decay Times of Rayleigh Waves Extended Array Evaluation Program
Special rept. 1 Apr 1972-31 Mar 1973
TEXAS INSTRUMENTS INC DALLAS SERVICES GROUP
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An approach to prediction of long-period Rayleigh wave signal persistence is taken through mean-time-between-failure and waiting time stochastic models. The estimate applies only to the generalized case of a network of recording stations and wide spatial distribution of earthquake sources. Rayleigh waves from Eurasian earthquakes reocrded on Very Long Period Experiment systems were analyzed to obtain data for the study. Successive time intervals between the maximum recorded amplitude, A , and the latest point of recorded signal equal to A2, the time between A2 and A4, A4 and A8, and etc. were measured until the signal amplitude reached tha ambient noise level. Resulting half-amplitude decay times Wn were found to follow a gamma probability law. The distribution of observed Wn fits this law with 0.90 confidence or greater according to the Chi-squared criterion. The results indicate that the probability distribution of half-amplitude decay times in earthquake Rayleigh waves can be readily estimated using appropriate gamma distribution parameters.
- Seismic Detection and Detectors