NEHRP Clearinghouse

Procedures for Selecting Earthquake Ground Motions at Rock Sites (Revised).
Idriss, I. M.
National Inst. of Standards and Technology, Gaithersburg, MD., March 1993, 40 p.
There are several procedures that can be used to select earthquake ground motions at a rock site. These procedures include: (1) utilization of motions previously recorded at rock sites during similar size earthquakes and at distances comparable to those under consideration; (2) estimation of a target spectrum and then selection of natural time histories whose spectral ordinates are comparable to those of the target spectrum for the period range of interest; (3) estimation of a target spectrum and then generation of a synthetic time history whose spectral ordinates provide a reasonable envelope to those of the target spectrum; or (4) use of simulation techniques starting with the source and propagating the appropriate wave forms to generate a suite of time histories that can then be used to represent the earthquake ground motions at the rock site of interest. For the purpose for which NIST plans to use the procedures outlined in the report, only procedures number (2) and number (3) are covered herein. Estimation of the target spectrum is based on currently available empirically derived attenuation relationships.
; Damping; Tremors; Earthquakes; Time studies; Seismic effects; Spectral response; Shock waves; Attenuation; Motion studies