Spatial seismic coefficients
Dynamic coefficients in the format of response spectra were proposed as simplified measures of spatial seismic effects on structures as well as for modeling non-homogeneous site amplification effects. For the propagation problems the influence of two principal parameters: propagation velocity and loss of coherence on spatial seismic vibrations has been studied in detail. For the site amplification problem the effect of presense of rock outcrop & soil layer simultaneously under two supports were investigated. The proposed coefficients may serve as partial multipliers in approximate engineering analyses.

For more information see: Journal of Engineering Mechanics, ASCE, vol.119, 1993, pp.2449-2460 and vol.122, 1996, pp.379-382, Engineering Structures, vol.24, 2002, pp.1485-1496.