Synthesis of Stochastic Representations of Ground Motions

A primary concern in problems dealing with earthquake or blast response is the proper definition of random force environments. Typical problems include the design of earthquake-resistant frames for electronic or mechanical facilities in a building, and the estimation of structural damage resulting from nuclear detonation in a given area. Normally it is necessary to create ground-motion data artificially from information derived from limited recordings. Therefore, in ground-motion analysis, as in many other fields of engineering physics, time series modeling or simulation problems emerge. This paper carries forward the concern with such problems. In a previous paper the statistical characteristics of a collection of earthquake ground-motion data were analyzed. 1 It was shown that a stationary random process of finite duration could be used to model the high-intensity phase of a ground-motion accelerogram. It was suggested that a narrowband stationary process be used. However, the narrowband process, like many other stationary models, fails to produce 521