Northridge USA 1994 (SPA)

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Event ID
199401171230
Event name
Northridge
Country
USA
Region in the country
California
World region
North America
Epicentral coordinates (long/lat)
POINT(-118.54 34.21)
WKT GIS format
GEMECD contributing partner
SPA
Event narrative

At 4:31 A.M. local time, Monday, January 17, 1994 the Northridge earthquake struck the San Fernando Valley region of Southern California with a moment magnitude measured at 6.7 and focal depth of 19 km.

The earthquake was centered 32 km west-northwest of Los Angeles along a south-dipping, blind thrust fault. Little if any surface faulting was produced.

The earthquake was felt throughout much of southern California and as far away as Turlock, California; Las Vegas, Nevada; Richfield, Utah and Ensenada, Mexico.

The maximum recorded acceleration exceeded 1.0g at several sites in the area with the largest value of 1.8g recorded at Tarzana, about 7 km south of the epicenter.

A maximum uplift of about 15 cm occurred in the Santa Susana Mountains and many rockslides occurred in mountain areas, blocking some roads. Some ground cracks were observed at Granada Hills and in Potrero Canyon. Some liquefaction occurred at Simi Valley and in some other parts of the Los Angeles Basin.

Date of occurrence (UTC)
1994-01-17
date
Time of occurrence (UTC)
12:30:55
time
Date of occurrence (local)
1994-01-17
date
Time of occurrence (local)
04:30:55
time
Day of the week (local)
Monday
Magnitude
6.7
Magnitude units
Moment (Mw)
Focal depth
18
km
Seismological data: source
USGS
Overall impact

Sixty people were killed, more than 7,000 injured, 20,000 homeless and more than 40,000 buildings damaged in Los Angeles, Ventura, Orange and San Bernardino Counties.

Severe damage occurred in the San Fernando Valley: maximum intensities of (IX) were observed in and near Northridge and in Sherman Oaks.

Lesser, but still significant damage occurred at Fillmore, Glendale, Santa Clarita, Santa Monica, Simi Valley and in western and central Los Angeles.

Damage was also sustained to Anaheim Stadium. Collapsed overpasses closed sections of the Santa Monica Freeway, the Antelope Valley Freeway, the Simi Valley Freeway and the Golden State Freeway.

Fires caused additional damage in the San Fernando Valley and at Malibu and Venice.

Preliminary estimates of damage are between 13 and 20 billion U.S. dollars.

(From USGS' Significant Earthquakes of the World 1994 at http://earthquake.usgs.gov/earthquakes/states/events/1994_01_17.php)

Overview data
Loss: Human Casualty
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People injured
7000
number
People injured: source
USGS

People seriously injured
138
number
People seriously injured: source
Peek-Asa et al (1998) Fatal and hospitalized injuries resulting from the 1994 Northridge earthquake, Intl. J. Epedemiology, vol. 27, pp. 459-465

People missing: comment

Unknown

People missing: status
N/A

People killed
33
number
People killed: source
http://earthquake.usgs.gov/earthquakes/states/us_deaths.php, OES (1995) and Peek-Asa et al (1998) Fatal and hospitalized injuries resulting from the 1994 Northridge earthquake, Intl. J. Epedemiology, vol. 27, pp. 459-465).
People killed: comment

the often quoted total of 60 fatalities includes a number cited by OES as "natural death due to earthquake related stress". Peek-Asa et al find 33 deaths directly caused by the earthquake, which is confirmed by OES.


People killed due to ground shaking
61
number
People killed due to ground shaking: comment

incl. 22 due to structural failure, 12 due to fatal physical injury not related to structural failure, 24 stress-related deaths (mostly due to heart attack) and 3 deaths due to respirator failure


People dying post catastrophe due to shaking: comment

Unknown

People dying post catastrophe due to shaking: status
N/A

People missing due to tsunami
0
number
People killed due to tsunami
0
number
People missing due to fire following: comment

Unknown

People killed due to fire following
2
number
People missing due to slope failures: comment

Unknown

People killed due to slope failures: comment

Unknown

Loss: Building damage
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Number of dwellings destroyed: status
Waiting for input

Number of dwellings damaged: status
Waiting for input

Total number of buildings destroyed by shaking
3000
number
Total number of buildings destroyed by shaking: source
OES (1995) The Northridge Earthquake of January 17, 1994: Report of Data Collection and Analysis, Part A: Damage & Inventory Data, EQE International for the Governor's Office of Emergency Services of the State of California, Sacramento, USA
Total number of buildings destroyed by shaking: comment

of 114,000 buildings inspected (presumably the significantly affected area), less than 3000 were red-tagged.

Total number of buildings destroyed by shaking: status
Less than

Number of buildings damaged by shaking
14500
number
Number of buildings damaged by shaking: source
OES (1995) The Northridge Earthquake of January 17, 1994: Report of Data Collection and Analysis, Part A: Damage & Inventory Data, EQE International for the Governor's Office of Emergency Services of the State of California, Sacramento, USA
Number of buildings damaged by shaking: comment

of 114,000 buildings inspected (presumably in the significantly affected area), 14,500 were red- AND yellow-tagged.


Number of dwellings destroyed by shaking: comment

Unknown


Number of dwellings damaged by shaking: comment

Unknown


Loss: Socioeconomic
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People homeless
20000
number
People homeless: source
USGS

Direct economic loss
24000
million US$
Direct economic loss: source
OES (1995) The Northridge Earthquake of January 17, 1994: Report of Data Collection and Analysis, Part A: Damage & Inventory Data, EQE International for the Governor's Office of Emergency Services of the State of California, Sacramento, USA

Indirect economic loss
44000
million US$
Indirect economic loss: source
OES (1995) The Northridge Earthquake of January 17, 1994: Report of Data Collection and Analysis, Part A: Damage & Inventory Data, EQE International for the Governor's Office of Emergency Services of the State of California, Sacramento, USA
Indirect economic loss: comment

The value of $44 billion is the best available, but only approximate, and was arrived at by pro-rating up insured losses to account for uninsured property.


Insured loss
15300
million US$
Insured loss: source
Munich Re
Insured loss: comment

Property Claims Services (PCS) estimated the insured losses at 7.2 billion US$ in August 1994 and at 10.4 billion US$ in January 1995


Demographics
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hide
Total number of buildings
114000
number
Total number of buildings: source
OES (1995) The Northridge Earthquake of January 17, 1994: Report of Data Collection and Analysis, Part A: Damage & Inventory Data, EQE International for the Governor's Office of Emergency Services of the State of California, Sacramento, USA