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Northridge, California Earthquake, January 17, 1994, Set 2 |
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.
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