Conversion of Historic Seismic Data at the Southern California Earthquake Data Center (SCEDC)

The Southern California Earthquake Data Center (SCEDC) archives and provides public access to continuous and event-based earthquake parametric and waveform data gathered by the Southern California Seismic Network. The mission of the SCEDC is to maintain an easily-accessible, well-organized, high-quality, searchable archive of earthquake data for research in seismology and earthquake engineering. The SCEDC has compiled and converted all available historic seismic data to create a single source of southern California earthquake data from 1932-present. The 1932-1976 era of seismic data was key-punched from the original phase cards into CUSP-format on a VAX system. The data was then imported into the SCEDC Oracle database, so phase and epicenter data is available for direct retrieval by users via STP. A problematic four-year span of CEDAR data from 1977-1980 is currently not accessible, but has been converted and is being processed to include magnitude information. The parametric data from 1981 to present has been loaded into the Oracle 9i database system and the waveforms for that time period have been converted to mSEED format and are accessible through the STP interface. Quality control of 1981-2000 historic parametric and waveform data has progressed using a detailed reverse-chronological examination and verification of magnitudes. Current efforts at the SCEDC are focused on continuing to expand the available seismic datasets, enhancing and expanding distribution methods, and providing rapid access to all datasets, historic and modern. Through the California Integrated Seismic Network, the SCEDC is working with the NCEDC to provide unified access to California earthquake data.