Automatic phase-detection and identification by full use of a single three-component broadband seismogram

Automatic-time picking continues to be a significant issue in seismogram an alysis. Any individual method is based on separation of signal and noise in a particular domain and cannot ensure consistent onset time picking under all source, receiver, path, and noise conditions. However, a combination of three methods based on differing aspects of seismograms can be used to pro vide automated and consistent phase detection and interpretation using a si ngle three-component record. For arrival detection, a combination of energy analysis, differences in instantaneous frequency, and an auto-regressive r epresentation of the seismic record are used to develop an algorithm for ro bust phase extraction, suitable for use in real time. The character of the phases is extracted using polarization analysis using complex traces to sep arate S- and P-wave phases. The combination of four different methods offer s a very effective technique for automatic arrival detection and associatio n from a single three-component broadband seismogram and from thence an app roximate event location procedure.