The Southern California network bulletin, January - December, 1989

The California Institute of Technology together with the Pasadena Office of the U.S. Geological Survey operates a network of approximately 280 remote seismometers in southern California. Signals from these sites are telemetered to the central processing site at the Caltech Seismological Laboratory in Pasadena. These signals are continuously monitored by computers that detect and record thousands of earthquakes each year. Phase arrival times for these events are picked by human analysts and archived along with digital seismograms. All data aquisition, processing and archiving is achieved using the CUSP system. These data are used to compile the Southern California Catalog of Earthquakes; a list beginning in 1932 that currently contains more than 180,000 events. This data set is critical to the evaluation of earthquake hazard in California and to the advancement of geoscience as a whole. This and previous Network Bulletins are intended to serve several purposes. The most important goal is to make Network data more accessible to current and potential users. It is also important to document the details of Network operation, because only with a full understanding of the process by which the data are produced can researchers use the data responsibly