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A Study of the Engineering Characteristics of the 1971 San Fernando Earthquake Records Using Time Domain Techniques.
Bond, W. E.; Dobry, R.; O'Rourke, M. J.
National Science Foundation, Washington, DC. Engineering and Applied Science., June 1980, 182 p.
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Accelerograms recorded at ground elevation during the 1971 San Fernando, California earthquake were examined by four time domain techniques: (1) the Husid plot of energy buildup; (2) root mean square acceleration; (3) principal planes of ground motion; and (4) the response envelope of a simple degree of freedom system. Through use of these techniques a part of the accelerograms that includes arrival of S-waves from the source was identified computationally. This strong part is characterized by two parameters--the duration and level of shaking. Horizontal plane root mean square acceleration was used to provide a measure of the level of shaking which is independent of the orientation of the recording devices. Attenuation of the root mean square acceleration with distance was generally consistent with an equation which relates the root mean square accelerations with the earthquake source parameters. A traveling Rayleigh wave was identified at two deep soil sites. Studies suggest this wave may have been caused by shallowness of the faulting process. These time domain techniques have demonstrated their usefulness in characterizing the San Fernando earthquake motions for engineering purposes.
Earthquake engineering; Earthquakes; Time measurement; San Fernando earthquake (1971); Secondary waves; California; Mathematical models; Rayleigh waves; Seismic waves