The spectral component of foundation motion is changed, and the motion of foundation is smaller than that of freefield.
相互作用改变了基底地震动的频谱组成，使基础处的地震动比自由场地震动小。
2
To an observer free of plate motion, ITRF velocity field is approximate.
对于不随板块运动的观察者，ITRF的速度场是近似的。
3
A 1d finite element method in time domain is developed, which is used to calculate the in-plane wave motion of freefield in elastic layered semispace by oblique seismic incidence.