National Geophysical and Solar-Terrestrial Data Center (NGSDC).

The National Geophysical and Solar-Terrestrial Data Center acquires, processes, archives, analyzes, and disseminates solid Earth and marine geophysical data as well as ionospheric, solar, and other space environment data; develops analytical, climatological, and descriptive products to meet user requirements; and provides facilities for World Data Center-A (Solid-Earth Geophysics, Solar Terrestrial Physics, and Glaciology). (a) Geophysical and solar-terrestrial data available from NGSDC include: (1) Marine geology and geophysics. Bathymetric measurement; seismic reflection profiles; gravimetric measurements; geomagnetic total field measurements; and geological data, including data on heat flow, cores, samples, and sediments. (2) Solar-Terrestrial physics. Ionosphere data, including ionograms, frequency plots, riometer and field-strength strip charts, and tabulations; solar activity data; geomagnetic variation data, including magnetograms; auroral data; cosmic ray data; and airglow data. (3) Seismology. Seismograms; accelerograms; digitized strong-motion accelerograms; earthquake data list (events since January 1900); earthquake data service with updates on a monthly basis. (4) Geomagnetic main field. Magnetic survey data and secular-change data tables. (b) Queries should be addressed to: National Geophysical and Solar-Terrestrial Data Center, National Oceanic and Atmospheric Administration, Boulder, CO 80303, tel. 303-499-1000, ext. 6215.