Spectral Analysis of Natural Seismic Events Using Autoregressive Techniques

This paper presents results illustrating the use of high-resolution spectral estimation methods in the analysis of natural seismic events produced by a small earthquake. The methods used are based on autoregressive (AR) data modelling, originally introduced by Burg as maximum-entropy spectral analysis. In addition, a recently proposed adaptive AR method is also examined. Comparisons with conventionally generated power spectra show that the higher resolution spectra computed using the AR technique provide additional useful information for these data. The adaptive AR results indicate that the signatures may be characterized by the early arrival of a high-frequency component near 0.009 Hz which decays to a value of 0.007 Hz at 25 s after onset.