The Northridge, California Earthquake of January 17, 1994: General Reconnaissance Report

Keywords: Northridge, California Earthquake, January 17, 1994, Postearthquake Investigations, Regional Geology, Seismological Aspects, Geotechnical Aspects, Strong Motion Records, Highway Bridges, Buildings, Damage, Seismic Performance, Industrial Facilities, Lifelines, Water Systems, Sewer Systems, Oil Pipelines, Gas Delivery Systems, Electrical Power Systems, Nonstructural Elements, Emergency Response, Economic Impact, and Earthquake Engineering.

Abstract: On January 17, 1994 at 4:31 a.m., a magnitude 6.6 earthquake struck the Los Angeles metropolitan area. Epicentered in the San Fernando Valley town of Northridge, California, the earthquake caused serious damage to buildings and sections of elevated freeways; ignited at least one hundred fires as it ruptured gas pipelines; and disrupted water supply systems. Fifty-seven people died, another 1,500 were seriously injured, and 22,000 were left homeless. Over 3,000 buildings, most of which were residential structures, were declared unsafe for reentry due to earthquake damage. This report presents the findings of numerous investigators who visited the Northridge area following the earthquake. Topics include seismology, geology and geotechnical issues; highway bridges and buildings; lifelines and utilities; nonstructural building elements; emergency response; and societal impacts. In addition, the authors provided some tentative conclusions based on their observations and experience in past earthquakes. These conclusions and recommendations are included in a separate section at the end of the report. Many of the observations and conclusions contained in this report are preliminary; it is not intended to be the final word on the earthquake, rather its purpose is to provide an additional increment of new information beyond that contained in earlier reports and to set the stage for further investigations.