Seismicity of Southern California: Earthquakes of ML 3.0 and Greater, 1975 through 1983

Abstract

The time period since the last published California Institute of Technology (CIT) earthquake catalog (Hileman 1974; Friedman 1976) has seen many changes in data analysis and reporting procedures at the Seismological Laboratory. CIT merged its operation with the U.S. Geological Survey (USGS) during this period. Digital recording (Johnson 1979) was introduced in 1977 and computer systems improved several times since. The seismic network itself expanded from 125 stations in 1975 to more than 200 in early 1983 (Figure 1). The result is an agglomeration of data that way take a superhuman effort to sort through. Much use can be made, however, of a timely earthquake catalog which is restricted to the larger earthquakes. We therefore present as complete and reliable a list of events of ML 3.0 and greater as possible, comprising 3,650 individual earthquakes.