This research is to emplace a 3-component seismometer at depth in the Cajon Pass borehole. At the 3.5 km depth of the borehole, this is important because this is a zone of seismogenic activity in crystalline rock, and deep sampling of local seismic events increases our understanding of the components of the P- and S- wave seismic spectra and the seismic coda in crust undisturbed by near surface phenomena. If spatial and temporal statistical properties of earthquake occurrence, for example, b-values and coda Q, contain important precursory information, the largest and cleanest seismogram sample set is available from sensors placed at depth. This research is a component of the National Earthquake Hazard Reduction Program.
