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El Centro Earthquake Page

Photo: U.S. Coast and Geodetic Survey


Time History Data File for North-South Component, time(sec) & Acceleration (G): elcentro.dat
The instrument that recorded the accelerogram was attached to the El Centro Terminal Substation Building’s concrete floor, and not in a free-field location. The record may have under-represented the high frequency motions of the ground because of soil-structure interaction of the massive foundation with the surrounding soft soil.

Vibrationdata Programs to Calculate Shock Response Spectrum:

SRS page

Earthquake Engineering Page
Time History Data Files from El Centro Site Imperial Valley Irrigation District

These file have two colums: time(sec) & Acceleration (G)




( Note that file elcentro_NS.dat is similar to the time history at the top of the page if either time history is multiplied by -1. There are different versions of the El Centro time histories available on the Internet. A future revision of this page will clarify this matter. )

Time History Data File Reference:

Pacific Earthquake Engineering Research Center
This reference notes that the orginal data source was:

Type of Digital Strong-Motion Data: Corrected
 USGS Description of the El Centro (Imperial Valley) Earthquake
Nine people were killed by the May 1940 Imperial Valley earthquake. At Imperial, 80 percent of the buildings were damaged to some degree. In the business district of Brawley, all structures were damaged, and about 50 percent had to be condemned. The shock caused 40 miles of surface faulting on the Imperial Fault, part of the San Andreas system in southern California. It was the first strong test of public schools designed to be earthquake-resistive after the 1933 Long Beach quake. Fifteen such public schools in the area had no apparent damage. Total damage has been estimated at about $6 million. The magnitude was 7.1.

 Recommended Books
1. A. Chopra, Dynamics of Structures: Theory and Applications to Earthquake Engineering, 2000.
2. Bruce A. Bolt Earthquakes (Earthquakes, 4th Ed) 1999.

3. Levy and Salvadori, Why Buildings Fall Down, 1994.

4. T. Lay and T. Wallace, Modern Global Seismology, Academic Press, New York, 1995.

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Please send comments and questions to Tom Irvine at: tomirvine@aol.com

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