Improved Data Access From the Northern California Earthquake Data Center

The NCEDC is a joint project of the UC Berkeley Seismological Laboratory and the USGS Menlo Park to provide a long-term archive and distribution center for geophysical data for northern California. Most data are available via the Web at http://quake.geo.berkeley.edu and research accounts are available for access to specialized datasets. Current efforts continue to expand the available datasets, enhance distribution methods, and to provide rapid access to all datasets. The NCEDC archives continuous and event-based seismic and geophysical time-series data from the BDSN, the USGS NCSN, the UNR Seismic Network, the Parkfield HRSN, and the Calpine/Unocal Geysers network. In collaboration with the USGS, the NCEDC has archived a total of 887 channels from 139 sites of the "USGS low-frequency" geophysical network (UL), including data from strainmeters, creep meters, magnetometers, water well levels, and tiltmeters. There are 336 active continuous data channels that are updated at the NCEDC on a daily basis. Geodetic data from the BARD network of over 40 continuously recording GPS sites are archived at the NCEDC in both raw and RINEX format. The NCEDC is the primary archive for survey-mode GPS and other geodetic data collected in northern California by the USGS, universities, and other agencies. All of the BARD data and GPS data archived from USGS Menlo Park surveys are now available through the GPS Seamless Archive Centers (GSAC), and by FTP directly from the NCEDC. Virtually all time-series data at the NCEDC are now available in SEED with complete instrument responses. Assembling, verifying, and maintaining the response information for these networks is a huge task, and is accomplished through the collaborative efforts of the NCEDC and the contributing agencies. Until recently, the NCSN waveform data were available only through research accounts and special request methods due to incomplete instrument responses. In the last year, the USGS compiled the necessary descriptions for for both historic and current NCSN instrumentation. The NCEDC and USGS jointly developed a procedure to create and maintain the hardware attributes and instrument responses at the NCEDC for the 3500 NCSN channels. As a result, the NCSN waveform data can now be distributed in SEED format. The NCEDC provides access to waveform data through Web forms, email requests, and programming interfaces. The SeismiQuery Web interface provides information about data holdings. NetDC allows users to retrieve inventory information, instrument responses, and waveforms in SEED format. STP provides both a Web and programming interface to retrieve data in SEED or other user-friendly formats. Through the newly formed California Integrated Seismic Network, we are working with the SCEDC to provide unified access to California earthquake data.