Database Development

Due to restrictions imposed by the USGS/MP NCSN CUSP event analysis system, the NCSN's authoritative catalog, phase data, amplitude, and coda readings were stored in flat files, rather than the NCEDC database. However, the NCEDC worked closely with the Northern California Earthquake Management Center (NCEMC) of the CISN to develop procedures allowing the USGS/MP to replace the CUSP analysis system with jiggle, the analysis tool developed by the SCSN, and to deliver earthquake parametric data in real-time to the NCEDC database. We developed the database tools to insert the NCEMC earthquake parametric information into databases in the real-time earthquake analysis systems, and extensively tested database replication between the NCEMC databases and the NCEDC database.

Starting in December 2006, the NCSN retired the CUSP system, and real-time earthquake parameters from the NCEMC has been inserted directly into the NCEMC and NCEDC databases, and reviewed with the jiggle analysis software. In collaboration with the NCSN, we developed the programs and procedures necessary to migrate the 1967-2006 NCSN catalog into the CISN parametric schema and have been performing quality control procedures on the data prior to entering the catalog into the database. During this time, we have continued to create flat-file hypoinverse files from the new data in the database in order to provide users with a single view of the entire NCSN catalog. Once the historic NCSN catalog has been entered into the database, the NCEDC will serve catalog and parametric searches from the database.

During 2002-2004, the NCEDC and NCSN jointly developed a system consisting of an extensive spreadsheet containing per-channel information that describes the hardware of each NCSN data channel and provides each channel with a SEED-compliant channel name. This spreadsheet, combined with a limited number of files that describe the central-site analog digitizer, FIR decimation filters, and general characteristics of digital acquisition systems, allows the NCSN to assemble its station history in a format that the NCEDC can use to populate the hardware tracking and instrument response database tables for the NCSN.

The NCEDC instrument response schema represents full multi-stage instrument responses (including filter coefficients) for the broadband data loggers. The hardware tracking schema represents the interconnection of instruments, amplifiers, filters, and data loggers over time, and is used to describe all of the UC Berkeley and USGS stations and channels archived at the NCEDC. All NCSN event waveform and continuous timeseries data has been converted from CUSP and Earthworm format to MiniSEED, and is available along with the UC Berkeley data and data from the other networks archived at the NCEDC in full SEED format.

The NCEDC has developed XML import and export procedures to provide better maintenance of the hardware tracking information and resulting instrument responses for stations in our database. When changes are made to either existing hardware or to station configurations, we export the current view in XML format, use a GUI-based XML editor to easily update the information, and import the changes back into the database. When adding new stations or hardware, we can easily use information from existing hardware or stations as templates for the new information. This allows us to treat the database as the authoritative source of information, and to use off-the-shelf tools such as the XML editor and XML differencing programs as part of our database maintenance procedures.

Additional details on the joint catalog effort and database schema development may be found at http://www.ncedc.org/db

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