Lifelines performance in the Landers and big bear (California) earthquakes of 28 June 1992

Abstract The southern California high desert and mountain area was hit by two earthquakes on Sunday, 28 June 1992. The epicenters for the Landers (Ms 7.5) and Big Bear (Ms 6.6) earthquakes were about 100 miles (160 km) east of Los Angeles, California. The most significant impact on lifelines was to the highway, water, and electrical systems. As a result of the large surface fault displacement in the Yucca Valley and very old pipe in other areas, there were hundreds of water pipeline breaks, and it took up to several weeks to fully restore service. Electrical service was disrupted throughout southern California owing to wires swinging together, which caused the automatic circuit breakers to trip. Most service was restored in seconds, and all service was restored by the next day. Also, these earthquakes caused closure of several state highways, as a result of surface fault displacement, cracking of pavement, and rock slides.