During the reporting period short-period data from several sites have been used to study the nature of the spectra from presumed explosions, to test a potential new discriminant, and to study depth phases. Surface- and body-wave magnitude data have been obtained and used to study regionalization phenomena. Preliminary studies of ultra-long-period data have been undertaken. Modifications of continental array processing methods have been completed and signal equalization studies initiated. Upgrading of software and hardware facilities has continued. (Author)