Simulated earthquake motions

Abstract

Simulated earthquake motions suitable for design calculations are generated with the aid of a digital computer. The artificial accelerograms are sections of a random process with a prescribed power spectral density, multiplied by envelope functions chosen to model the changing intensity at the beginning and end of real accelerograms. Two each of four different types of acce lerograms have been generated to represent ground acceleration for a variety of earthquakes. Type A models the acceleration in a Magnitude 8 shock and type B the motion expected in a Magnitude 7 earthquake. The shaking expected in the epicentral area of a Magnitude 5 or 6 earthquake is modeled by type C and the motion close to the fault in a shallow Magnitude 4 or 5 shock is represented by type D. The two records of each type were generated to serve as the two horizontal components of earthquake shaking, or as two independent samples of possible ground shaking in the same type of event. Included in the report are accelerograms and derived velocity and displacement curves as well as response spectra.