Preliminary evaluation of ALPA

An initial estimate of the utility of the Alaskan Long-Period Array, based on 1970–71 data, has been made. Areas of investigation which relate to signal enhancement include several potential means of array processing, selection of appropriate bandpass filters, and the efficacy of various approaches to the matched-filtering of surface waves. Both direct and indirect estimates of the detectability of long-period surface waves have been made. Data reflecting the performance of Ms, AR, and AL discrimination parameters are included. The results presented here were obtained with the nine sites in the southern half of the array which were available during the time period covered.