Summary

Description

On Monday, January 17, 1994, an earthquake occurred that took 57 lives and caused $10 billion in property damage. This slide set includes damaged structures in more distant communities including Sylmar, Fillmore, Granada Hills, Reseda, Van Nuys, Sherman Oaks, Chatsworth, Santa Monica, and Los Angeles. At 4:31 a.m. (local time) on Monday, January 17, 1994, a magnitude 6.8 earthquake twenty miles west northwest of downtown Los Angeles (34 degrees 13' N, 118 degrees 32'W) awoke nearly everyone in southern California. Damage was most extensive in the San Fernando Valley, the Simi Valley, and in the northern part of the Los Angeles Basin. After the earthquake, a total of 24,000 dwellings were vacated. The death toll from the quake was 57. The total cost of the earthquake is estimated to be at least $10 billion.The Shock - The main shock beneath the Northridge suburb occurred on a shallowly-dipping, previously unknown thrust fault. The rupture started at a depth of about twelve miles and, during the course of the main shock, traveled upward and northward, spreading both eastward and westward. Rock on south side of the fault surged upward and over the rock to the north side. As a result of the quake, the San Fernando Valley is slightly narrower and the mountains just north of the valley are slightly higher. Damage to building structures outside the epicentral area was severe, spotty in geographic distribution, and spread over a large area. Significant damage was reported as far as Fillmore in the west, Valencia in the north, and Anaheim in the south-east. The distribution of unsafe buildings was affected by the strength of the earthquake shaking, and the type and density of the construction. It was no surprise that unreinforced masonry and older concrete frame constructions suffered structural damage. However damage and collapses in newer structures particularly parking garages, commercial buildings, and apartment complexes was surprising and even alarming. The building construction community may need to reexamine implementation and enforcement of minimum code mandated performance criteria. In the northwestern San Fernando Valley, surface disruptions have been identified. A prominent zone of surface fissures also occurred across Balboa Boulevard in the Granada Hills. Several pipelines appeared to have pulled apart in approximately the same general area. Generally the accelerations for this earthquake were higher over a larger area, than one might expect for an earthquake of this size. Santa Monica, about 14.5 miles from the epicenter and across the Santa Monica Mountains was also heavily damaged. Most of the damage occurred in an east-west trending belt within the northern portion of the city, and extended westward into Pacific Palisades and eastward into west Los Angeles and Hollywood. Two hundred million dollars in damage occurred. One hundred thirty-four buildings were unsafe for occupancy and 396 others were damaged enough to limit access.Damaged Buildings - Many businesses with operations in Los Angeles were disrupted by the earthquake. Companies shut plants and offices, and more than forty retailers reported heavy damage. Apartment complexes all over the San Fernando Valley were severely damaged.Infrastructure - On Monday, the day of the quake, 680,000 in the Los Angeles area were without power, gas, or phone service. Power outages swept throughout the Los Angeles basin and were reported as far away as Alberta and British Columbia due to the load problems stemming from the quake. Forty thousand were without water. Although the phone system survived relatively intact, some long-distance services into and out of parts of Los Angeles were lost because of equipment damage and power failure. Water trunk lines were broken, and water surged down some streets. Gas from a ruptured gas line ignited, and the resulting fire destroyed several homes. Explosions from ruptured gas mains occurred in the midst of the flooding from broken water mains.Transportation - The earthquake closed several major highways and freeways. At the Fairfax, La Cienaga, and Venice Boulevard intersection with the Santa Monica Freeway, an overpass fell closing the nation's busiest freeway. Spans collapsed in the interchange between the Golden State Freeway (I-5) and the Antelope Valley Freeway (SR-14), in the northern San Fernando Valley. A motorcycle police officer died in a fall off broken highway slab. Rock slides closed roads to Malibu Canyon and Topanga Canyon. The highway and freeway collapses nearly isolated some communities and caused commutes of as much as four hours. A Southern Pacific train was derailed near the earthquake epicenter spilling 5,000 gallons of sulfuric acid and 3,000 gallons of diesel fuel.Hospitals - The most severe damage to health care facilities occurred in the Santa Monica area where a total of five facilities were declared unsafe. The Community Hospital in Granada Hills had to evacuate its top floors and treat people in the parking lot and in debris-strewn hallways. Three hundred people were evacuated from Veterans Administration Medical Center. At damaged Sepulveda Veterans Administration Hospital a stream of transit authority buses and private ambulances ferried 330 patients to other facilities. Three people died of quake-related heart attacks at Cedars Sinai Medical Center. The Northridge earthquake is significant since it is the most expensive earthquake and one of the most expensive natural disasters in United States history yet it occurred on a previously unknown fault.