A note on energy of strong ground motion during Northridge, California, earthquake of January 17, 1994

The average contours of spatial variations of energy of strong earthquake ground motion during the 1994 Northridge, California earthquake change monotonically and slowly over distances as large as tens of kilometers. Comparison of those contours with the depth of sediments and with vertical offsets of the basement rocks along the faults in the Los Angeles basin implies predominantly horizontal flow of energy through the deep wave-guides of the Los Angeles basin. If the source-to-station distances were measured along the three-dimensional wave paths through these sedimentary wave-guides, rather than along straight lines, as is common at present, the accuracy of empirical scaling equations for prediction of strong-motion energy would be improved significantly.

► Redistribution of energy radiation of strong earthquake ground motion by three-dimensional geology.
► Attenuation of wave energy along three-dimensional paths.
► The role of sedimentary basins as wave-guides for strong motion energy.