This report on the seismological and engineering aspects of the 17 January, 1994, Northridge earthquake was printed on 24 January, 1994, one week after the main event. Its purpose is to provide a brief overview of preliminary observations related to the earthquake. The primary audience is seismologists, engineers and related professionals in the earthquake hazard and earthquake risk mitigation field. The report is preliminary in the sense that significant data collection and analysis remain to be completed. Reports containing more complete data and analysis may be issued at a later date. Immediately following the 17 January, 1994, Northridge earthquake, the Earthquake Engineering Research Center dispatched a reconnaissance team to the ep...