Abstract
The displacement and stress induced in surface layers by earthquake ground motions are correlated with the response spectrum of strong-motion records obtained on the ground surface. An empirical formula for the duration of ground motion in an earthquake during which the acceleration may exceed an arbitrary threshold value at stations near the epicenter is given. On the basis of experimental data of soil liquefaction a procedure for estimating the pore-water pressure in soils, when subjected to an arbitrary stress history, is proposed and applied to an observed value at a railway embankment in the Tokachioki earthquake, 1968 with due consideration for the spectral character and the duration of ground motion.
