The Caltech digital seismograph

A digital data logger has been constructed at the California Institute of Technology for recording the signals from long-period Press-Ewing seismometers. Three-component data are continuously digitized at the rate of 10 samples per second with an 86-db dynamic range and stored on magnetic tape. With a tape speed of 0.5 inch/sec, data for a 24-hour period may be recorded on one 10 1/2-inch reel. An editing system is then used to select interesting events and convert them to a form compatible with the IBM 7090 computer for further reduction and analysis.