Combined Catalog

We are building a HF-specific data archive from the existing waveform data that have been collected by the heterogeneous set of recording systems in operation along the Hayward fault (i.e. the NHFN, SHFN, NCSN, and BDSN continuous and triggered waveforms). Recently we have taken the NHFN triggers collected during operations between 1995.248 and 1998.365 (recorded on portable RefTek recorders) and origin times from the Northern California catalog for this time period and undertaken a massive association of event and trigger times. The purpose of the effort is to compile a relatively uniform catalog of seismic data to low magnitudes and extending back in time to the beginning of reliable HFN data collection. The process has reduced nearly a million individual time segments to 316 real events along the Hayward fault during the period-an increase in the number of events of a factor of about 2.5 to 3 over the Northern California catalog alone in the same area.