NEHRP Clearinghouse

Title
Separation of Body and Surface Waves in Strong Ground Motion Records.
File
PB298975.pdf
Author(s)
Liang, G. C. C.; Duke, C. M.; Mal, A. K.
Source
National Science Foundation, Washington, DC. Engineering and Applied Science., March 1976, 168 p.
Identifying Number(s)
UCLA-ENG-7627
Abstract
A method to separate body and surface waves in strong motion accelerograms is devised based on a linear system model. Described is the development and application of the model, and subsequent changes in design. The mathematics of linear system analysis, source functions, directionality and travel path effects, and local site properties are included. Mainshock records from the 1971 San Fernando Earthquake are used to test the method. The existence of large unrealistic peaks in the separated body and surface wave spectra indicating false data led to the introduction of various methods to eliminate these peaks from the spectrum. Several of these methods, described here, prove to be effective in different ways. The corrected body and surface wave spectra show expected characteristics. It is suggested that further development in the system model is needed to improve the surface wave transfer functions.
Keywords
Body waves; Surface waves; Seismic waves; Mathematical models; Shock spectra; Earthquake engineering; Soil dynamics; Computer programs; Earthquakes