Agenda - City of Santa Monica

The 1994 Northridge Earthquake
The January 17, 1994 magnitude 6.7 Northridge Earthquake (thrust fault), with its
epicenter beneath Reseda, produced severe ground motions, caused 57 deaths, 9,253
injuries and left over 20,000 people displaced within the Los Angeles area. It was the
most expensive disaster in the history of Santa Monica, which sustained more than
$250 million in damage. More than 530 buildings, including 2,300 housing units, were
red or yellow-tagged, rendering them uninhabitable or with limited accessibility. An
estimated 16,000 apartments, condominiums or houses sustained some damage and
were green-tagged, or still inhabitable.
Because of the severe damage in Santa Monica, city officials implemented a number of
measures to expedite recovery efforts, including a streamlined permit process and fee
waivers, as well as rent increases to cover earthquake repairs in rent-controlled
buildings. Funds received from the Federal Emergency Management Agency included
$93.4 million for home repairs, temporary housing, infrastructure repairs and retrofitting
to help lessen the effects of future disasters.
The earthquake affected almost every building on the Santa Monica College campus
with an estimated $80 million spent on the recovery effort. Santa Monica Hospital
Medical Center suffered significant damage leading to the hospital’s partnership with
UCLA. The hospital’s pavilion and tower sustained about $15 million in immediate
damage, forcing the tower’s closure for nine months. All of the hospital’s operations
were consolidated into the pavilion.
The hospital stayed open for three days before it was forced to shut down completely
because of the extensive damage. On October 3, 1994, Saint John’s was fully
operational minus its north wing, which was demolished. The cost of repairs totaled $32
million.
Magnitude and Intensity of an Earthquake
During an earthquake, energy stored up in faults is released. In major earthquakes, the
energy released is sufficient to break a large portion of the causative fault. In the worstcase
scenario the fault ruptures along its entire length. When the fault ruptures, seismic
waves propagate, resulting in the ground vibrations normally felt during an earthquake.
Ground shaking generally causes the most widespread damage in an earthquake.
Strong ground motion can catastrophically damage vulnerable structures such as
freeway overpasses and unreinforced masonry buildings. Ground shaking can also
trigger a variety of secondary hazards such as liquefaction, landslides, soil subsidence,
fire, dam failure and even toxic chemical releases.
USGS Earthquake Magnitude policy is to use Moment Magnitude (M), an earthquake
magnitude measurement very similar to the Richter measurement, which measures the
amount of energy released by the fault movement in relation to the fault area broken to
determine the magnitude of an earthquake.
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