Some problems in the application of spectrum techniques to strong-motion earthquake analysis

A comparison of analog and digital computation of strong-motion earthquake response spectra is made, and it is shown that the preference as to method will depend mainly on availability of computing equipment. The accuracy of analog response spectrum computations is shown to be compatible with the limitations of the original ground acceleration data. The accuracy of the customary approximate relationship between the displacement response spectrum and the velocity response spectrum is investigated, and the validity of the simplifications are shown for typical strong-motion earthquake applications. The relationship between the response spectrum and the Fourier spectrum is developed, and a comparison as to suitability for earth-quake engineering problems is given.