61 Site effects on strong ground motions

摘要: This chapter focuses on site effects strong ground motions. Site play a very important role in characterizing seismic motions because they may strongly amplify (or deamplify) at the last moment just before reaching surface of or basement man-made structures. Because high level amplification caused by effects, which can be almost two orders magnitude, one cannot neglect them engineering practice. Physical modeling as medium wave propagation from source to receiver reference position is most rigorous approach effects. By theoretically, for any arbitrary vibration simulated. If incident so intense that soft-soil sediments go nonlinear regime, then introduce constitutive relationship physical model. layered structure complicated and has lens-like structures here there, construct irregular interfaces between layers reproduce scattering through these interfaces. After establishing an appropriate model around target site, kind strong-motion prediction becomes possible. The also reviews empirical approaches site-effects studies—namely, separation method (sometimes called inversion method) based coda microtremors.