The Southern California Earthquake Data Center (SCEDC)

The SCEDC is the primary archive facility for seismic information for southern California earthquakes. The data archive consists of earthquake parameters and travel-time picks from 1932 to the present, waveform recordings from 1981 to the present recorded by the Southern California Seismic Network (SCSN) and Caltech-USGS TriNet, SAR satellite images of southern California, and some regional refraction profiles of the crust and mantle. Data from portable instrument deployments after the 1992 Joshua Tree and Landers earthquakes, and from the 1994 Northridge earthquake, are also stored in this facility. The Data Center is currently archiving nearly 3,000 data channels from 375 stations. An average of 20,000 earthquakes are processed and archived each year. The history of the SCEDC, the current state of data collection, the design of the database and archival system, user access to the system, and the plans for the future are outlined in this article. In particular, we discuss how the data from a large seismic array are stored, and we explain modern methods for accessing the data