| Northridge, California Earthquake, January 17, 1994, Set 1 |
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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 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. This slide set depicts the damage
in Northridge-the epicentral area. Photos show damage to a shopping center, parking
garages, and the interior and exterior of apartment buildings. 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 earthquake
epicenter was at the intersection of Wilbur Avenue and Arminta Street in Northridge,
a college community 20 miles northwest of downtown Los Angeles. The main shock occurred
on a shallowly-dipping, previously-unknown thrust fault beneath the suburb of Northridge.
The rupture begin at about twelve miles depth and traveled upward and northward, spreading
both eastward and westward. The focal mechanism of the main shock from both first
motions and teleseisms shows a N 60 degrees west striking and 35 degrees to 45 degrees
south dipping plane. Rock on southside of the fault surged upward and over the rock
on the north side. As a result of the quake, the San Fernando Valley is slightly narrower
and themountains just north of the valley are slightly higher. The Northridge Fashion
Mall was extensively damaged by the earthquake. Bullocks Department Store in the mall
collapsed. One parking structurecollapsed into a pile about twenty feet high. Other
department stores and parking structures were also damaged. Windows were shattered
throughout the mall. Severe damage and partial collapses were seen also in other,
smaller, shopping centers near the epicenter. Northridge Meadows Apartment Complex
- Not far from the Northridge Fashion Mall sixteen people were killed when the 164-unit
Northridge Meadows Apartment collapsed. There was an area of several square miles
in Northridge where there was intense damage to apartments built in the 1960's and
early 1970's, prior to the latestrevisions in the building codes for multi-family
housing. Many of these apartment buildings had "soft" first stories. California State
University Campus - Most of the sixty buildings on the campus performed well and there
were no injuries or deaths on the campus. One parking structure collapsed and three
buildings were severely damaged and were unrepairable. Fifteen to twenty buildings
will require structural repairs and retrofitting to meet code. Inside the buildings
the contents were severely disturbed. Freight Train Derailed - A sixty-four car Southern
Pacific freight train carrying hazardous material was derailed between the communities
of Chatsworth and Northridge. Sulfuric acid was released from one of the sixteen tank
cars carrying the substance. Two thousand gallons of diesel fuel spilled from the
locomotive. Northridge Community Center Hospital - At Northridge Community Center,
located near the epicenter, patients in wheelchairs were rushed outside. There was
no water, no power, and no phones. At the same time the center was deluged with requests
for treatment from people suffering injuries in the earthquake. 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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